The Cassini Radio and Plasma Wave Science (RPWS) calibrated
summary key parameter data set includes reduced temporal and
spectral resolution spectral information calibrated in units of
spectral density for the entire Cassini mission. This data set
includes calibrated values binned and averaged within 1 minute by
0.1 decade spectral channels for all times during the mission
including the two Venus flybys, the Earth flyby, the Jupiter
flyby, interplanetary cruise, and the entire Saturn tour. Data
for this data set are acquired by the RPWS Low Frequency Receiver
(LFR), Medium Frequency Receiver (MFR), and High Frequency
Receiver (HFR). Data are presented in a set of
fixed-record-length tables. This data set is intended to provide
numerical summary data which can be used in conjunction with other
Cassini fields and particles key parameter data sets to establish
trends, select events, or simply as a browse data set for the
Cassini RPWS archive. This data set should be among the first
used by a user of any of the RPWS archive as it will lead one to
information required to search for more detailed or highly
specialized products.

The Cassini Radio and Plasma Wave Science (RPWS) Low Rate Full Resolution Calibrated (RPWS_LOW_RATE_FULL) is a data set including all spectral density measurements acquired by the RPWS in units of electric or magnetic field spectral density. This
data set includes calibrated values for each frequency channel for
each sensor for all times during the mission including the two
Venus flybys, the Earth flyby, the Jupiter flyby, interplanetary
cruise, and the entire Saturn tour. Data for this data set are
acquired from the RPWS Low Frequency Receiver (LFR), Medium
Frequency Receiver (MFR), Medium Frequency Digital Receiver (MFDR)
(which can be used to replace MFR band 2 data) and High Frequency
Receiver (HFR). Data are presented in a set of tables organized
so as to have fixed-length records for ease in data handling.
This data set is intended to be the most comprehensive and
complete data set included in the Cassini RPWS archive. A browse
data set is included with these data which provides for a
graphical search of the data using a series of thumbnail and
full-sized spectrograms which lead the user to the particular data
file(s) of interest. This data set should be among the first used
by a user of any of the RPWS archive as it will lead one to
information required to search for more detailed or highly
specialized products.

This data set includes 1-minute averages of the electric and
magnetic wave spectra obtained during the period that the Galileo
plasma wave receiver was operated during the Jupiter orbital
mission (prime, GEM and GMM). The parameter provided for the
electric field spectrum is the electric field spectral density
in units of V**2/m**2/Hz. The magnetic field spectrum is
provided in units of magnetic field spectral density, nT**2/Hz.
The spectral information is averaged and binned into 49
logarithmically-spaced channels from about 6 Hz to 5.6 MHz for the
electric measurements and 34 channels from about 6 Hz to 75 kHz for
the magnetic. Note that these 'channels' do not generally
correspond to the 158 specific channels described in the instrument
description document. The reduction in spectral resolution for this
data set was performed in order to make the set more conducive to
use as a browse data set. The sources of this browse data set are
the High Frequency Receiver, Sweep Frequency Receiver, and Spectrum
Analyzer which make up the Low Rate Science portion of the PWS.

This data set includes 1-minute averages of the electric and
magnetic wave spectra obtained during the period that the Galileo
plasma wave receiver was operated during the Jupiter orbital
mission (prime, GEM and GMM). The parameter provided for the
electric field spectrum is the electric field spectral density
in units of V**2/m**2/Hz. The magnetic field spectrum is
provided in units of magnetic field spectral density, nT**2/Hz.
The spectral information is averaged and binned into 49
logarithmically-spaced channels from about 6 Hz to 5.6 MHz for the
electric measurements and 34 channels from about 6 Hz to 75 kHz for
the magnetic. Note that these 'channels' do not generally
correspond to the 158 specific channels described in the instrument
description document. The reduction in spectral resolution for this
data set was performed in order to make the set more conducive to
use as a browse data set. The sources of this browse data set are
the High Frequency Receiver, Sweep Frequency Receiver, and Spectrum
Analyzer which make up the Low Rate Science portion of the PWS.

This dataset contains 24 hour duration dynamic spectrogram plots from the combined STEREO A and B Waves instrument.
The plots are provided in several file formats (PNG, Postscript and PDF) and there are renditions in color and grayscale with and without additional lines of time series data indicating the instrument operating status. These plots all reside within the same directory structure subdivided by year. The "new" subdirectory contain plots at a higher resolution but currently are not available for dates early in the mission.
These data consist of output from the SWAVES HFR and LFR receivers.
? the High Frequency Receivers (HFR) - for spectral analysis and direction finding of radio noise generated from a few solar radii (16 MHz) to about half an Astronomical Unit
(125 kHz)
? the Low Frequency Receiver (LFR) - for spectral analysis and direction finding from about half an Astronomical Unit (160 kHz) to one AU (2.5 kHz).

The CDF file contains 1 minute averaged radio intensity data from both the Ahead and Behind s/c.
A description of the STEREO/WAVES instrument is provided in:
Bougeret, J.L, et al. (2008), S/WAVES: The Radio and Plasma Wave Investigation on the STEREO Mission, Space Science Reviews, 136, 487-528.
The STEREO / WAVES (SWAVES) instruments provide unique and critical observations for all primary science objectives of the STEREO mission, the generation of CMEs, their evolution, and their interaction with Earth's magnetosphere. SWAVES can probe a CME from lift-off to Earth by detecting the coronal and interplanetary (IP) shock of the most powerful CMEs, providing a radial profile through spectral imaging, determining the radial velocity from ~2 RS (from center of sun) to Earth, measuring the density of the volume of the heliosphere between the sun and Earth, and measuring important in situ properties of the IP shock, magnetic cloud, and density compression in the fast solar wind stream that follows.
SWAVES measures the fluctuation electric field present on three orthogonal monopole antennas mounted on the back (anti-sunward) surface of the spacecraft. Each monopole antenna unit is a 6 m long Beryllium-Copper (BeCu) ?stacer? spring. The three units deploy from a common baseplate that also accommodates the preamplifier housing. The 6 m length was chosen to put the antenna quarter-wave resonance near the top of the SWAVES HFR2 frequency band.
These data consist of output from the SWAVES HFR and LFR receivers.
? the High Frequency Receivers (HFR) - for spectral analysis and direction finding of radio noise generated from a few solar radii (16 MHz) to about half an Astronomical Unit
(125 kHz)
? the Low Frequency Receiver (LFR) - for spectral analysis and direction finding from about half an Astronomical Unit (160 kHz) to one AU (2.5 kHz).

from URAP Users Notes: Guide To The Archiving Of Ulysses Radio And Plasma Wave Data
by Roger Hess, Robert MacDowall, Denise Lengyel-Frey
March 15, 1995 - version 1.0
revised March 24, 1999 - version 1.1
revised June 8, 1999 - version 1.2
These color plots present URAP radio and plasma wave data in a
format referred to as dynamic spectra. For the daily plots, the time
resolution is 128 seconds, providing high-time resolution across the
entire frequency range of the URAP receivers. The 10-day plots
use 10-minute resolution data, which permits good detection of
bursty wave activity. The 26-day plots use 1-hour resolution data;
these plots correspond to the other Ulysses 26-day plot intervals,
but the ability to identify wave activity is reduced. The power of
the electric or magnetic field is shown in color as a 2-dimensional
function of time and frequency. The plots include data from the
URAP Radio Astronomy Receivers (RAR), Plasma Frequency
Receiver (PFR), and Waveform Analyzer (WFA). Refer to the
documentation for the 10-minute average archive data files, as well
as Stone et al. (1992), for more general information on these
instruments. Here, we describe the choices that were made in
generating these plots.
1. Formats - These plots are available in 2 formats: GIF files for
viewing with a web browser and Postscript files for high quality
printed copies. The resolution of the GIF files is 776 x 600 pixels,
a compromise between smaller size for network transfer and larger
size for improved resolution. The Postscript files are sized to fit
both 8.5x11 inch paper or A4 paper. The daily unzipped (zipped)
Postscript files are typically 400-440 kB ( 130-140 KB) in size; the
daily GIF files are typically 200-230 kB in size. (The 10-day and
26-day plots are similar in size.)
2. Data units - The data and the associated color bar are plotted in
units of decibels, an old radio astronomer unit for describing signal
to background ratio on a logarithmic scale. Specifically,
Data_in_dB = 10. * log10(total power/background power)
The data for electric field observations are in units of microvolts**2
Hz**(-1) as are the calculated background levels. The units for
magnetic field observations (the bottom panels on the page) are
nT**2 Hz**(-1). The data for the 1-day plots are comparable to the
squared values of data in the URAP UFA 10-minute files.
Although the ratio (total power-background power)/background
power permits one to see weaker events in such plots, it is more
sensitive to background determination and enhances the noise
seen in the plots. Therefore, it is not used here.
3. Backgrounds - The background levels as a function of frequency
for the RAR and WFA are determined from the data for the day,
because they vary throughout the mission. The PFR background
does not vary significantly with time, so fixed background levels
are used. For each of the instruments, the backgrounds vary with
the instrument mode, so separate sets of backgrounds are derived
for each mode that is present. (Modes are discussed below).
The PFR and WFA backgrounds also depend significantly on bit
rate. For the RAR the background level selected is the lowest 3%
of the data for each frequency; for the PFR and WFA, the
background level selected is the lowest 10% of the data for each
frequency. The higher number is chosen for the WFA because the
data are substantially noisier than the RAR.
It should be noted that this type of background subtraction will
remove any signal at a given frequency that is constant throughout
the day. An example is the quasithermal noise line ("plasma line")
in the RAR data, when the density does not vary throughout the
day.
Note that for 10-day and 26-day plots, in particular, the background
determination might result from a few hours of very low intensity
data, which will cause all the other data, referenced to that
background, to appear enhanced. This is an unfortunate
consequence of determining the background levels from intervals
of minimum data intensity.
4. Modes and other labels - Each of the instruments has several
modes that affect the data display. The telemetry bit rate is also
an important parameter. The key modes and the bit rate are
shown on the dynamic spectrum as the thickness (or nonexistence)
of a line.
The RAR Hi and Lo bands are plotted in separate panels because
they are commanded separately. For each band, the spin-plane
and spin-axis antennas can be either summed or separate. If the
RAR Hi or Lo band instrument is in summed mode, then a white
line for the appropriate band is present under the RAR plot.
Summed mode provides data used for 3-dimensional direction
finding at the expense of a higher background level. Because the
backgrounds will differ between summed and separate modes,
backgrounds are calculated for both modes when they are present.
Although the RAR is typically operated in a mode where
measurements are made at all 76 frequencies, there are times
when only a subset of the frequencies are sampled (called
Measure mode). In these cases, the data plotted are interpolated
in frequency to give a clearer picture of the events that might be
taking place. These intervals are evident from the appearance of
the data, which is smoothed in frequency; see Nov. 6, 1990, where
the RAR Lo band is in Measure mode for the first 18 hours of the
day. This example also shows the RAR hi band in a rarely-used,
single frequency mode. If the Measure mode data occupy less
than 10% of the day; they are not interpolated, because the events
occurring at these times should be clear from the non-Measure
mode data, and it is useful to see which frequencies are being
sampled. The Jupiter flyby interval (e.g., Feb. 8, 1992) includes
examples of short intervals of measure mode.
The bit rate significantly affects the PFR and WFA backgrounds. If
the science data bit rate is 1024 bps, it is indicated by a thick line,
512 bps is indicated by a thin line, and low ("emergency") bit rates,
either 256 or 126 bps, by no line.
The PFR operates in one of 3 modes - fast scan, slow scan, or
fixed tune (see Stone et al., 1992). These 3 modes have different
backgrounds and generate different interferences for the WFA
instrument. Fast scan is shown by the white line under the PFR
plot, slow scan is in progress if there is no line, and fixed tune is a
single frequency mode (evident from the PFR data display),
typically used in 1 hour/day intervals.
The WFA instruments can sample either the electrical (E) antennas
or the (B-field) search coil. For the low band of the WFA B field
data (< 8 Hz), either By or Bz data are telemetered. The available
parameter is shown by the white line above the B (WFA) plot
(present=By, absent=Bz).
5. Interpolation - In addition to the interpolation discussed above
for the RAR, the RAR data are interpolated to remove data gaps of
384 seconds or less. We interpolate the RAR data because the
events observed in the RAR, such as solar type II and type III
radio bursts, are mostly smoothly varying on time scales of a few
minutes. Therefore, they are easier to visualize and interpret when
data gaps are interpolated. For the events in the PFR and WFA
data, predominantly bursty wave events, interpolation is not
necessary and not performed. An exception occurs when the data
telemetry rate is either 256 or 128 bps; then the WFA data are
interpolated in time because they are not sampled every 128 sec.
Finally, the RAR Hi band data, for which there are only 12
channels of data, are interpolated to fit a logarithmic frequency
scale with 37 equivalent frequencies.
6. Interference and other issues affecting data interpretation - Each
of these instruments, like all sensitive wave receivers, is affected
by interference from other sources. For the RAR Hi band, an
interference signal at 81 kHz is produced by the Ulysses GAS
instrument. Depending on the mode in which the GAS instrument
is operating, this interference can occur from 0 to 24 hours per
day. If an algorithm determines that this interference is present in
more than about 10% the RAR data for the day, we remove the 80
kHz data and interpolate from adjacent frequencies. The RAR Hi
band also has an enhanced background at 120 kHz (source
unknown). Subtraction of this enhanced background can cause
artifacts in other events, like type III bursts. See Nov. 30, 1990 as
an example.
The RAR Lo band has an interference line at 8.75 kHz and odd
harmonics caused by the Ulysses traveling wave tube amplifier
(TWTA), which is part of the high gain telemetry system. In
general, this signal is removed by the background subtraction,
sometimes producing artifacts in weak radio events or the thermal
noise spectrum at these frequencies
The PFR experiences interference from the URAP Sounder; these
data are removed from the plots and appear as short data gaps.
The background levels of the PFR depend on bit rate, PFR mode,
and the cadence of the URAP Fast Envelope Sampler (FES data
not presented in these plots); these background variations can
affect the appearance of events at the transition from one mode to
another.
The WFA data are affected by numerous interferences, of which
the URAP PFR is the dominant source. WFA "backgrounds" vary
significantly depending on whether the PFR is in fast or slow scan
mode or fixed tune, so separate backgrounds are calculated for
each of these. The URAP Sounder also causes interference;
these data are removed from the plots and appear as short data
gaps. Spacecraft thruster operations produce a variety of artifacts
in the data; since we have no indication of these in our telemetry,
they are not flagged on the plots. Examples may be seen on Feb
23, 1995 at 12:00 and on Feb. 25, 1995 at 15:00. An interesting
"interference" is seen to disappear on Dec. 17, 1990; this is when
the spacecraft nutation was stopped. This is best seen on the 26-
day plots.
To summarize, there are a variety of artifacts in the wave data that
affect interpretation. These can result from corrupted telemetry
values (producing bad pixels (most evident in the RAR plots, see
March 23, 1993, from 6:00-14:00, or August 16, 1991, a very good
example of very bad data quality), interferences (e.g., non-physical,
block-like structures sometimes seen in the highest frequencies of
the WFA E and B data (see March 14, 1995)), or changes of the
instrument mode or the physical medium (e.g., a short interval of
data with a very low signal level defines a background for the rest
of the day that is not appropriate; see Nov. 4, 1990, when the Ex
antenna was deployed).
7. Spacecraft location - At the lower left on the plots, 4 parameters
related to the location of Ulysses at the mid-time of the plot are
printed:
a) the Ulysses-Sun (U-S) distance in AU,
b) the heliographic latitude (Hlat_U) of Ulysses in degrees,
c) the Ulysses-Sun-Earth (U-S-E) angle in degrees, and
d) the Ulysses-Jupiter (U-J) distance in AU.
These are among the most relevant parameters for interpreting the
URAP data. Additional parameters, as well as a graphic showing
the Ulysses location relative to the Sun, Earth, and Jupiter, can be
found at the URAP Home Page at Goddard Space Flight Center (see below).
8. For additional information on these plots or on the URAP data,
contact the PI of the URAP investigation, Dr. Robert MacDowall, at
phone: 1-301-286-2608
fax: 1-301-286-1683
email: robert.macdowall@gsfc.nasa.gov.
The URL for the URAP Home Page at Goddard Space Flight
Center is
http://urap.gsfc.nasa.gov/

This data set contains 144 second averages of the electric field
intensities from the Ulysses Unified Radio and Plasma Wave
Instrument Radio Astronomy Receiver (URAP/RAR).
The following notes are taken from the Guide to Archiving of Ulysses URAP Data
revised January 27, 2010 - version 1.3
ftp://ftp.rssd.esa.int/pub/ulysses/URAP/docs/others/archived_data_user_guide.html
Appendix C: USER'S GUIDE TO RAR 144 SECOND AVERAGED DATA FILES
The time period of 144 seconds was used for the averaging period because that is the basic cycling time of the instrument. The RAR continually cycles through a list of frequencies. There are 16 lists and the list currently in use is chosen by telecommand. The time period to complete the list is 144 seconds for the high band of the receiver (for telemetry bit rates of 1024 and 512 bps, the cycle time is 64 seconds for bit rates of 256 and 128 bps), after which the instrument begins with the list again. Therefore this period was chosen for the averaging period.
The format of the data is indicated by the following Fortran statement which can be used to read the data:
DIMENSION F(0:75)
READ(1,'(I4,2I2,1X,3I2,1X,5I2,12(/6E12.4),/4E12.4)')
+ IYEAR, IMONTH, IDAY, IHOUR, IMINUTE, ISECOND,
+ LO_POL_MODE, LO_SUM_MODE, HI_POL_MODE, HI_SUM_MODE,
+ IBPS, F
The variables are defined as follows:
The date and time of the beginning of the averaging period are given in IYEAR, IMONTH, IDAY, IHOUR, IMINUTE, ISECOND.
LO_POL_MODE and HI_POL_MODE are the polarization modes of the low and high receiver bands. Their values are defined as:
1: Polarization on.
2: Polarization off.
3: Polarization mode switched during the averaging interval.
4: Polarization mode was unknown (usually due to a data gap).
LO_SUM_MODE and HI_SUM_MODE are the polarization modes of the low and high receiver bands. Their values are defined as:
1: Summation on.
2: Summation off.
3: Summation mode switched during the averaging interval.
4: Summation mode was unknown (usually due to a data gap).
1: Summation on.
2: Summation off.
3: Summation mode switched during the averaging interval.
4: Summation mode was unknown (usually due to a data gap).
IBPS indicates the telemetry bit rate during the averaging interval. Its values are defined as:
1: 128 bps.
2: 256 bps.
3: 512 bps.
4: 1024 bps.
5: Bit rate changed during the averaging period.
6: Bit rate unknown - usually due to a data gap.
F is a vector containing the average signal for the 76 frequencies of the low and high bands. Elements 0 through 63 are from the low band receiver and correspond to frequencies of 1.25+0.75*N Khz where N is the element number (0..63). The frequency channels from 64 to 75 correspond to the following frequencies:
F(64): 52 KHz
F(65): 63 KHz
F(66): 71 KHz
F(67): 100 KHz
F(68): 120 KHz
F(69): 148 KHz
F(70): 196 KHz
F(71): 272 KHz
F(72): 387 KHz
F(73): 540 KHz
F(74): 740 KHz
F(75): 940 KHz
The units of the data are microvolt/Hz**.5 measured at the receiver input terminals. To convert to electric field strength the given data must be divided by the effective length of the antenna. This is complicated by the fact that the effective length depends on the antenna impedance which is affected by the plasma conditions local to the Ulysses spacecraft. The impedance will also depend on the frequency. In general, the RAR frequency channels that are well above the local electron plasma frequency are not affected by the plasma conditions and the effective length of 23 meters can be used. When the RAR is in summed, rather than separate, mode the determination of field strengths is even more difficult.
Description of the Unified Radio and Plasma Wave Instrument
Radio Astronomy Receiver
The Radio Astronomy Receiver is divided into two parts, a low
frequency receiver and a high frequency receiver. The low
frequency receiver has 64 channels that cover the frequency range
from 1.25 to 48.0 kHz in linear steps of 0.75 kHz. The high
frequency receiver has 12 channels that cover the range from 52
kHz to 940 kHz in approximately logarithmic steps.
The high frequency receiver is usually operated in what is called
"measure" mode, which causes the receiver to step repeatedly
through a list of frequencies that is determined by a ROM on
board the spacecraft. There are 16 different lists and one of
them is chosen by telecommand. The different lists emphasize
different frequency ranges, so as to maximize the information
received depending on the type of phenomena being studied. Some
of the lists include all 12 possible frequency channels while
other lists skip some of the frequencies. The list that has been
used for most of the mission does include all frequecies, but
there may be times when other lists have been used. At these
times only a subset of the frequencies will be present.
The low frequency receiver can be operated in measure mode (with
its own set of lists of 8 or 16 frequencies) or in "linear sweep"
mode where it steps through a contiguous set of frequencies. In
linear mode, all 64 frequencies can be stepped through, or a
subset of 32 frequencies can be chosen using the lower half,
middle half, or upper half of the frequencies. For most of the
mission, the low frequency receiver has been operated in linear
mode with all 64 frequencies but there have been periods when it
has operated in measure mode or in in linear mode with less than
64 frequencies. During these periods only a subset (8, 16, or
32) of the 64 possible frequencies will appear.
Besides the intensity of a signal reaching the spacecraft, the
RAR can also, when operated in particular modes, determine
additional information about the source of the radiation,
including its direction relative to the location of Ulysses, its
angular size, and its polarization. This is most efficiently
done with the signal from the X and Z axis antennas summed
together electronically either with or without a phase shift
added between the two signals. Although this additional
information cannot be recovered from the averaged data, the mode
does have a large effect on the background signal level, so the
mode of high and low frequency receivers is given in the data as
either summed (X and Z antenna combined) or separate (X antenna
alone).
Reference: Astron. Astrophys. Suppl.
Ser., 92(2), 291-316 (1992).

This data set contains 144 second averages of the electric field
intensities from the Unified Radio and Plasma Wave
Instrument Radio Astronomy Receiver.
Units are microVolt/Hz**0.5 measured at the
receiver input terminals. To convert to electric field strength
the given data must be divided by the effective length of the
antenna. This is complicated by the fact that the effective
length depends on the antenna impedance which is affected by the
plasma conditions local to the Ulysses spacecraft. The impedance
will also depend on the frequency. In general, the RAR frequency
channels that are well above the local electron plasma frequency
are not affected by the plasma conditions and the effective
length of 23 meters can be used. When the RAR is in summed,
rather than separate, mode the determination of field strengths
is even more difficult.
The time period of 144 seconds was used for the averaging period
because that is the basic cycling time of the instrument. The
RAR continually cycles through a list of frequencies. There are
16 lists and the list currently in use is chosen by telecommand.
The time period to complete the list is 144 seconds for the high
band of the receiver (for telemetry bit rates of 1024 and 512
bps, the cycle time is 64 seconds for bit rates of 256 and 128
bps), after which the instrument begins with the list again.
Therefore this period was chosen for the averaging period.
Notes on the Radio Astronomy Receiver
from URAP User Notes
http://helio.esa.int/ulysses/archive/urap_un.html
The Radio Astronomy Receiver is divided into two parts, a low
frequency receiver and a high frequency receiver. The low
frequency receiver has 64 channels that cover the frequency range
from 1.25 to 48.0 kHz in linear steps of 0.75 kHz. The high
frequency receiver has 12 channels that cover the range from 52
kHz to 940 kHz in approximately logarithmic steps.
The high frequency receiver is usually operated in what is called
"measure" mode, which causes the receiver to step repeatedly
through a list of frequencies that is determined by a ROM on
board the spacecraft. There are 16 different lists and one of
them is chosen by telecommand. The different lists emphasize
different frequency ranges, so as to maximize the information
received depending on the type of phenomena being studied. Some
of the lists include all 12 possible frequency channels while
other lists skip some of the frequencies. The list that has been
used for most of the mission does include all frequecies, but
there may be times when other lists have been used. At these
times only a subset of the frequencies will be present.
The low frequency receiver can be operated in measure mode (with
its own set of lists of 8 or 16 frequencies) or in "linear sweep"
mode where it steps through a contiguous set of frequencies. In
linear mode, all 64 frequencies can be stepped through, or a
subset of 32 frequencies can be chosen using the lower half,
middle half, or upper half of the frequencies. For most of the
mission, the low frequency receiver has been operated in linear
mode with all 64 frequencies but there have been periods when it
has operated in measure mode or in in linear mode with less than
64 frequencies. During these periods only a subset (8, 16, or
32) of the 64 possible frequencies will appear.
Besides the intensity of a signal reaching the spacecraft, the
RAR can also, when operated in particular modes, determine
additional information about the source of the radiation,
including its direction relative to the location of Ulysses, its
angular size, and its polarization. This is most efficiently
done with the signal from the X and Z axis antennas summed
together electronically either with or without a phase shift
added between the two signals. Although this additional
information cannot be recovered from the averaged data, the mode
does have a large effect on the background signal level, so the
mode of high and low frequency receivers is given in the data as
either summed (X and Z antenna combined) or separate (X antenna
alone).
Reference: Astron. Astrophys. Suppl.
Ser., 92(2), 291-316 (1992).

Data Set Overview
=================
Instrument P.I. : Rochus E. Vogt
Data Supplier : National Space Science Data Center
Data sampling rate : variable (1 hr for FPHA data, 15 min.
for all others)
Data Set Start Time : 1979-02-28T00:00:00.000Z
Data Set Stop Time : 1979-03-21T23:45:00.000Z
(The following description has been adapted from
[NSSDCCRS1979])
As its name implies, the Cosmic Ray Subsystem (CRS) was
designed for cosmic ray studies [STONEETAL1977B]. It consists
of two high Energy Telescopes (HET), four Low Energy Telescopes
(LET) and The Electron Telescope (TET). The detectors have
large geometric factors (~ 0.48 to 8 cm^2 ster) and long
electronic time constants (~ 24 [micro]sec) for low power
consumption and good stability. Normally, the data are
primarily derived from comprehensive ([Delta]E[1], [Delta]E[2]
and E) pulse-height information about individual events.
Because of the high particle fluxes encountered at Jupiter and
Saturn, greater reliance had to be placed on counting rates in
single detectors and various coincidence rates. In inter-
planetary space, guard counters are placed in anticoincidence
with the primary detectors to reduce the background from
high-energy particles penetrating through the sides of the
telescopes. These guard counters were turned off in the Jovian
magnetosphere when the accidental anticoincidence rate became
high enough to block a substantial fraction of the desired
counts. Fortunately, under these conditions the spectra were
sufficiently soft that the background, due to penetrating
particles, was small.
The data on proton and ion fluxes at Jupiter were obtained with
the LET. The thicknesses of individual solid-state detectors
in the LET and their trigger thresholds were chosen such that,
even in the Jovian magnetosphere, electrons made, at most, a
very minor contribution to the proton counting rates
[LUPTON&STONE1972]. Dead time corrections and accidental
coincidences were small (< 20%) throughout most of the
magnetotail, but were substantial (> 50%) at flux maxima within
40 R[J] Of Jupiter. Data have been included in this package
for those periods when the corrections are less than ~ 50% and
can be corrected by the user with the dead time appropriate to
the detector (2 to 25 [micro]sec). The high counting rates,
however, caused some baseline shift which may have raised
proton thresholds significantly. In the inner magnetosphere,
the L[2] counting rate was still useful because it never rolled
over. This rate is due to 1.8- to 13-MeV protons penetrating
L[1] (0.43 cm^2 ster) and > 9-MeV protons penetrating the
shield (8.4 cm^2 ster). For an E^-2 spectrum, the two groups
would make comparable contributions; but in the magnetosphere,
for the E^-3 to E^-4 spectrum above 2.5 MeV [MCDONALDETAL1979],
the contribution from protons penetrating the shield would be
only 3 to 14%.
The LET L[1]L[2]L[4] and L[1]L[2]L[3] coincidence-
anticoincidence rates give the proton flux between 1.8 and 8
MeV and 3 to 8 MeV with a small alpha particle contribution
(~10^-3). Corrections are required for dead time losses in
L[1], accidental L[1]L[2] coincidences and anticoincidence
losses from L[4]. Data are given only for periods when these
corrections are relatively small. In addition to the rates
listed in the table, the energy lost in detectors L[1], L[2]
and L[3] was measured for individual particles. For protons,
this covered the energy range from 0.42 to 8.3 MeV. Protons
can be identified positively by the [Delta]E vs. E technique,
their spectra obtained and accidental coincidences greatly
reduced. Because of telemetry limitations, however, only a
small fraction of the events could be transmitted, and
statistics become poor unless pulse-height data are averaged
over a period of one hour.
HET and LET detectors share the same data lines and pulse-
height analyzers; thus, the telescopes can interfere with one
another during periods of high counting rates. To prevent such
an interference and explore different coincidence conditions,
the experiment was cycled through four operating modes, each
192 seconds long. Either the HETs or the LETs were turned on
at a time. LET-D was cycled through L[1] only and L[1]L[2]
coincidence requirements. The TET was cycled through various
coincidence conditions, including singles from the front
detectors. At the expense of some time resolution, this
procedure permitted us to obtain significant data in the outer
magnetosphere and excellent data during the long passage
through the magnetotail region.
Some of the published results from this experiment required
extensive corrections for dead time, accidental coincidences
and anticoincidences ([VOGTETAL1979A], [VOGTETAL1979B];
[SCHARDTETAL1981]; [GEHRELS1981]). These corrections can be
applied only on a case-by-case basis after a careful study of
the environment and many self-consistency checks. They cannot
be applied on a systematic basis and we have no computer
programs to do so; therefore, data from such periods are not
included in the Data Center submission. The scientists on the
CRS team will, however, be glad to consider special requests if
the desired information can be extracted from the data.
Description of the Data
-----------------------
(1) LD1 RATE gives the nominal > 0.43-MeV proton flux cm^-2
s^-1 sr^-1. This rate includes all particles which pass
through a 0.8 mg/cm^2 aluminum foil and deposits more than
220 keV in a 34.6 [micron] Si detector on Voyager 1 (209
keV, 33.9 [microns] on Voyager 2) Therefore, heavy ions,
such as oxygen and sulfur are also detected; however,
their contribution is believed to be relatively small.
Only a small percentage of the pulses in this detector are
larger than the maximum energy that can be deposited by a
proton. Heavy ions would produce such large pulses,
unless their energy spectra were much steeper than the
proton spectrum. The true flux, F[t], can be calculated
from the data:
F
F[t] = ----------------
1 - 1.26x10^-4 F
and corrections are small for F < 1000 cm^-2 s^-1.
(2) LD2 RATE is not suitable for an absolute flux
determination and is given in counters per s. The detector
responds to protons and ions that penetrate either (a) 0.8
mg/cm^2 Al plus 8.0 mg/cm^2 Si and lose at least 200 keV
in a 35 [micron] Si detector (1.8 to 13 MeV) or (b) pass
through > 140 mg/cm^2 Al. For an E^-2 proton spectrum, the
contributions from (a) and (b) would be about equal;
however, the proton spectrum is substantially softer
throughout most of the magnetosphere and the detector
should respond primarily to (a). Dead time corrections
are given by
R
R[t] = ----------------
1 - 2.55x10^-5 R
where R is the count rate in counts/s. Thus, correction to
the supplied data are small for R < 4000 c/sec, but become
80 large in the middle magnetosphere that the magnitude of
even relative intensity changes becomes uncertain.
(3) LD L[1].L[2]. L[4]. SL COINCIDENCE RATE gives the total
proton flux (cm^-2 s^-1 sr^-1) between ~ 1.8 and ~ 8.1 MeV
with a small admixture of alpha particles. Accidental
coincidences become subst

Data Set Overview
=================
Version 1.1
-----------
The SEDR based data provided as part of this data set were
originally reviewed and archived with the NSSDC and PDS as
version 1.0 (DATA_SET_ID = VG1-J-POS-4-48.0SEC). Version 1.1
includes additional columns not present in the previous
version, 96 second rather than 48 second time samples, times
converted to 'PDS Style' or ISO standard, and upgrading of
PDS labels and templates to version 3.2. The SPICE based
data that are also part of this data set were not previously
archived with the PDS. This version 1.1 data set replaces
previously archived versions.
Data Set Description
--------------------
This data set consists of Voyager 1 Jupiter encounter
ephemeris data in System III (1965) left handed coordinates
covering the period 1979-03-03 to 1979-03-16. Two versions,
both covering the same time period, but containing slightly
different data, are provided. One version was generated by
the Voyager MAG team from Voyager 1 SEDR, the other by the
PDS/PPI node using the VG1_JUP.BSP and PCK00003.TCP SPICE
kernels.
Two versions of the spacecraft ephemeris data are provided as
an attempt to correct some of the problems in the Voyager
SEDR while preserving the ability to reproduce early results.
The original SEDR data has a variety of problems which may
affect the knowledge of the spacecraft position, or
conversely, the timing associated with certain events such as
ring plane crossings. The SPICE SPK kernel provided on this
disk includes corrections to some, but not all, of the
problems associated with the Voyager SEDR. The Navigation
and Ancillary Information Facility (NAIF) at JPL may issue a
new Voyager SPK kernel in the future that will further
improve the knowledge of the spacecraft location in inertial
space.
There are other differences in the in the two versions of
ephemeris data that are the result of improvements in the
knowledge of some of the physical constants associated with
Jupiter and its moons. Since the Voyager era, there have
been updates to the orientation of the jovian spin axis right
ascension and declination, the radius of Jupiter, as well as
the orbital characteristic and other physical parameters of
many of the moons of Jupiter. These changes affect the
stated position of the spacecraft in jovigraphic coordinate
systems like System III without changing the position of the
spacecraft in inertial space. The spin rate of Jupiter is
not changed from the System III (1965) rate of 9h 55m
29.71sec (870.536 deg/day). The SPICE planetary constants
kernel (PCK) contains both the current IAU definitions of the
physical constants for the bodies within in the jovian system
(as data) as well as the older IAU definitions (as comments).
This is an ASCII text file (PCK00003.TCP) and users of the
ephemeris data are encouraged to review it.
SEDR generated ephemeris
------------------------
Instrument P.I. : N/A
Data Supplier : NSSDC (Voyager MAG Team)
Data sampling rate : 96 seconds
Data Set Start Time : 1979-03-03T00:00:35.978Z
Data Set Stop Time : 1979-03-16T23:59:08.185Z
SPICE generated ephemeris
-------------------------
Instrument P.I. : N/A
Data Supplier : S. Joy
Data sampling rate : 48 seconds
Data Set Start Time : 1979-03-03T00:00:35.978Z
Data Set Stop Time : 1979-03-16T23:59:56.185Z
Parameters
==========
SEDR generated ephemeris
------------------------
PARAMETER RESOLUTION/ DESCRIPTION
NAME UNITS
time 96.0 Sec time of the sample (UT) in the format
yyyy-mm-ddThh:mm:ss.sssZ
m65536 counts spacecraft clock counts
mod60 counts
fds_line counts
sc_x R[J] jovicentric (System III) cartesian
sc_y R[J] cartesian position vectors: X, Y, and
sc_z R[J] Z
vel_x km/s jovicentric X, Y, and Z spacecraft
vel_y km/s velocity components
vel_z km/s

Data Set Overview
=================
This data set consists of Voyager 1 Jupiter encounter ephemeris
data in Heliographic coordinates covering the period 1979-02-26
to 1979-03-24. Two versions, both covering the same time
period, but containing slightly different data, are provided.
One version was generated by the Voyager MAG team from Voyager
1 SEDR, the other by the PDS/PPI node using the VG1_JUP.BSP and
PCK00003.TPC SPICE kernels.
Two versions of the spacecraft ephemeris data are provided as
an attempt to correct some of the problems in the Voyager SEDR
while preserving the ability to reproduce early results. The
original SEDR data has a variety of problems which may affect
the knowledge of the spacecraft position, or conversely, the
timing associated with certain events such as ring plane
crossings. The SPICE SPK kernel provided on this disk includes
corrections to some, but not all, of the problems associated
with the Voyager SEDR. The Navigation and Ancillary
Information Facility (NAIF) at JPL may issue a new Voyager SPK
kernel in the future that will further improve the knowledge of
the spacecraft location in inertial space.
There are other differences in the in the two versions of
ephemeris data that are the result of improvements in the
knowledge of some of the physical constants associated with
Jupiter and its moons. Since the Voyager era, there have been
updates to the orientation of the jovian spin axis right
ascension and declination, the radius of Jupiter, as well as
the orbital characteristic and other physical parameters of
many of the moons of Jupiter. These changes affect the stated
position of the spacecraft in jovigraphic coordinate systems
like System III without changing the position of the spacecraft
in inertial space. The spin rate of Jupiter is not changed
from the System III (1965) rate of 9h 55m 29.71sec (870.536
deg/day). The SPICE planetary constants kernel (PCK) contains
both the current IAU definitions of the physical constants for
the bodies within in the jovian system (as data) as well as the
older IAU definitions (as comments). This is an ASCII text
file (PCK00003.TCP) and users of the ephemeris data are
encouraged to review it.
SEDR generated ephemeris
------------------------
Data Supplier : NSSDC
Data sampling rate : 96 seconds
Data Set Start Time : 1979-02-26T00:00:35.897Z
Data Set Stop Time : 1979-03-24T22:47:56.304Z
SPICE generated ephemeris
-------------------------
Data Supplier : S. Joy
Data sampling rate : 48 seconds
Data Set Start Time : 1979-02-26T00:00:35.897Z
Data Set Stop Time : 1979-03-24T22:49:32.304Z
Parameters
==========
SEDR generated ephemeris
------------------------
PARAMETER RESOLUTION/ DESCRIPTION
NAME UNITS
time 96.0 Sec. time of the sample (UT) in the format
yyyy-mm-ddThh:mm:ss.sssZ
m65536 counts spacecraft clock counts
mod60
fds_line
sc_x AU heliographic cartesian coordinates
sc_y position vectors: X, Y, and Z
sc_z
vel_x km/s heliocentric X, Y, and Z spacecraft
vel_y velocity components
vel_z
sc_r AU heliographic spherical coordinates
sc_lat degrees position vectors: range, latitude, and
sc_lon degrees longitude
SolEquatorial_to_HG solar equatorial to heliographic
coordinates rotation matrix containing
9 1pe15.8 elements
HG_to_EarthOrbTrue heliographic to earth orbit true
coordinates rotation matrix containing
9 1pe15.8 elements
Spacecraft_to_HG payload (spacecraft) to heliographic
coordinates rotation matrix containing
9 1pe15.8 elements
SPICE generated ephemeris
-------------------------
PARAMET

DATA SET OVERVIEW
=================
Version 1.1
-----------
This version 1.1 data set replaces the version 1.0 data set
(DATA_SET_ID = VG1-J-LECP-4-15MIN) previously archived with
the PDS. Data records from the version 1.0 data set provided
data for each of 8 sectors, plus the average for all sectors
in a separate record for each channel. This resulted in 9
repeated times per channel. Data records for the version 1.1
data set provide all data for a given channel and time period
(8 sectors, plus the average for all sectors) in a single
record. Other changes to this version include upgrading of
the associated labels and templates to PDS version 3.2
compliance, modification of the time formats and flag values.
Data Set Description
--------------------
This data set consists of resampled data from the Low Energy
Charged Particle (LECP) experiment on Voyager 1 while the
spacecraft was in the vicinity of Jupiter. This instrument
measures the intensities of in-situ charged particles (>26 keV
electrons and >30 keV ions) with various levels of
discrimination based on energy, mass species, and angular
arrival direction. A subset of almost 100 LECP channels are
included with this data set. The LECP data are globally
calibrated to the extent possible (see below) and they are time
averaged to about 15 minute time intervals with the exact
beginning and ending times for those intervals matching the
LECP instrumental cycle periods (the angular scanning periods).
The LECP instrument has a rotating head for obtaining angular
anisotropy measurements of the medium energy charged particles
that it measures. The cycle time for the rotation is variable,
but during encounters it is always faster than 15 minutes.
Thus, the full angular anisotropy information is preserved with
this data. The data is in the form of 'rate' data which has
not been converted to the usual physical units. The reason is
that such a conversion would depend on uncertain determinations
such as the mass species of the particles and the level of
background. Both mass species and background are generally
determined from context during the study of particular regions.
To convert 'rate' to 'intensity' for a particular channel one
performs the following tasks: 1) Decide on the level of
background contamination and subtract that off the given rate
level. Background is to be determined from context and from
making use of sector 8 rates (sector 8 has a 2 mm Al shield
covering it). 2) Divide the background corrected rate by the
channel geometric factor and by the energy bandpass of the
channel. The geometric factor is found in entry
'CHANNEL_GEOMETRIC_FACTOR' as associated with each channel
'CHANNEL_ID'. To determine the energy bandpass, one must judge
the mass species of the of the detected particles (for ions but
not for electrons). The energy band passes are given in
entries 'MINIMUM_INSTRUMENT_PARAMETER' and
'MAXIMUM_INSTRUMENT_PARAMETER' in table 'FPLECPENERGY', and are
given in the form 'energy/nucleon'. For channels that begin
their names with the designations 'CH' these bandpasses can be
used on mass species that are accepted into that channel (see
entries 'MINIMUM_INSTRUMENT_PARAMETER' AND
'MAXIMUM_INSTRUMENT_PARAMETER' in table 'FPLECPCHANZ', which
give the minimum and maximum 'Z' value accepted -- these
entries are blank for electron channels). For other channels
the given bandpass refers only to the lowest 'Z' value
accepted. The and passes for other 'Z' values are not all
known, but some are given in the literature (e.g.
[KRIMIGISETAL1979A]). The final product of these instructions
will be the particle intensity with the units: counts/(cm^2 str
sec keV).
This figure represents the structure of a single data record. Note that the
'SECTOR_STRUCTURE' (SECTOR1, SECTOR2, etc.) are not columns, but rather a
grouping of the DATA_VALUE and STANDARD_DEVIATION columns.
SECTOR1 SECTOR2 AVERAGE
__________________ __________________ __________________
____ | _____ _________ || _____ _________ | | _____ _________ |
| |||DATA ||STANDARD ||||DATA ||STANDARD || ||DATA ||STANDARD ||
|TIME|||VALUE||DEVIATION||||VALUE||DEVIATION|| ... ||VALUE||DEVIATION||
|____|||_____||_________||||_____||_________|| ||_____||_________||
|__________________||__________________| |__________________|
Parameters
==========
Electron Rate
-------------
Sampling Parameter Name : TIME
Data Set Parameter Name : ELECTRON RATE
Sampling Parameter Resolution : 15.000000
Sampling Parameter Interval : 15.000000
Data Set Parameter Unit : COUNTS/SECOND
Noise Level : 0.000000
Sampling Parameter Unit : MINUTE
A measured parameter equaling the number of electrons hitting
a particle detector per specified accumulation interval. The
counted electrons may or may not be discriminated as to their
energies (e.g. greater than E1, or between E1 and E2).

Version 1.1
-----------
This version 1.1 data set replaces the version 1.0 data set
(DATA_SET_ID = VG1-J-MAG-4-1.92SEC) previously archived with PDS.
Changes to this version include the addition of data columns not
included in version 1.0, the modification of time format and flag
values, and upgrade of associated labels and catalog templates to
PDS version 3.2.
Data Set Overview
=================
This data set includes calibrated magnetic field data acquired by
the Voyager 1 Low Field Magnetometer (LFM) during the Jupiter
encounter. Coverage begins in the solar wind inbound to Jupiter and
continues past the last outbound bowshock crossing. The data are in
System III (1965) (SYS3) coordinates and have been averaged from the
60 ms instrument sample rate to a 1.92 second sample rate. All
magnetic field measurements are given in nanoTesla (nT). The
magnetic field data are calibrated (see the calibration description
included in the Voyager 1 Magnetometer instrument catalog file for
details).
Parameters
==========
The full LFM instrument sample rate is 1 sample per 0.06 seconds.
Full telemetry resolution 'detail' data must be obtained from the
instrument team. These data have been resampled at 1.92 seconds from
the detail data.
The LFM has eight dynamic ranges. The instrument is designed switch
between dynamic ranges automatically depending upon the observed
magnetic field magnitude and fluctuations. Instrument digitization
uncertainty depends upon dynamic range as indicated in the following
table (from [BEHANNONETAL1977]).
-----------------------------------------------
LFM Dynamic ranges and quantization uncertainty
-----------------------------------------------
Range (nT) Quantization (nT)
-----------------------------------------------
1. +/- 8.8 +/- .0022
2. +/- 26 +/- .0063
3. +/- 79 +/- .019
4. +/- 240 +/- .059
5. +/- 710 +/- .173
6. +/- 2100 +/- .513
7. +/- 6400 +/- 1.56
8. +/- 50,000 +/- 12.2
Processing
==========
Voyager EDR's undergo the following processing in order to produce
these 1.92 second averaged summary data:
* Read EDR
* Unpack header block (rec. id, s/c id, tel. mode, FDS counts,
data flags)
* Convert selected time tags to integer time (yy/ddd/hh:mm:ss.fff)
* Unpack sub-header block (MAG status words, plasma data)
* Unpack science block (MAG counts)
* Convert counts to gammas
* Apply sensor and boom alignment matrices
* Rotate (optional) 1.92 second averages while averaging detail
gammas to create 1.92 second averages
* Write Summary record
Counts are measured onboard using 12 bit words that may represent
values ranging from 0-4096. Integer counts are converted to magnetic
field units (gammas) by subtracting a zero offset, from the measured
MAG value and multiplying this difference by the sensitivity of the
instrument.
Data
====
The data files are given in ASCII, fixed field width, comma
delimited tables. The record structure is described in the following
table:
--------------------------------------------------------------------
1.92 Second System III (1965) Coordinates
-------------------------------------------------------------------
Column Type Description
-------------------------------------------------------------------
time a23 spacecraft event time (UT) of the sample in the
format: yyyy-mm-ddThh:mm:ss.sss
sclk a12 spacecraft clock in the format:
MOD65536:MOD60:FDS-LINE
mag_id i1 magnetometer ID (1 = LFM, 2 = HFM)
Br f9.3 average of detail magnetic field R component in nT
Btheta f9.3 average of detail magnetic field Theta component in
nT
Bphi f9.3 average of detail magnetic field Phi component in
nT
Bmag f

Version 1.1
-----------
This version 1.1 data set replaces the version 1.0 data set
(DATA_SET_ID = VG1-J-MAG-4-48.0SEC) previously archived with PDS.
Changes to this version include the addition of data columns not
included in version 1.0, the modification of time format and flag
values, and upgrade of associated labels and catalog templates to
PDS version 3.2.
Data Set Overview
=================
This data set includes calibrated magnetic field data acquired by
the Voyager 1 Low Field Magnetometer (LFM) during the Jupiter
encounter. Coverage begins in the solar wind inbound to Jupiter and
continues past the last outbound bowshock crossing. The data are in
System III (1965) (SYS3) coordinates and have been averaged from the
9.6 second summary data to a 48 second sample rate. All magnetic
field measurements are given in nanoTesla (nT). The magnetic field
data are calibrated (see the calibration description included in the
Voyager 1 Magnetometer instrument catalog file for details).
Ephemeris data, provided in 96 second sampled System III (1965)
coordinates, have been merged into the data files for this data set.
The ephemeris data, generated from Voyager 1 SEDR and provided by
the Voyager MAG Team, are part of the data set
VG1-J-POS-6-SUMM-S3COORDS-V1.1. The position vectors for times at
which ephemeris is not provided have been flagged.
Parameters
==========
The full LFM instrument sample rate is 1 sample per 0.06 seconds.
Full telemetry resolution 'detail' data must be obtained from the
instrument team. For this data set, the data have been resampled to
48 seconds from 9.6 second averages. The 9.6 second data were
resampled from 1.92 second averages which were in turn resampled
from the detail data.
The LFM has eight dynamic ranges. The instrument is designed switch
between dynamic ranges automatically depending upon the observed
magnetic field magnitude and fluctuations. Instrument digitization
uncertainty depends upon dynamic range as indicated in the following
table (from [BEHANNONETAL1977]).
-----------------------------------------------
LFM Dynamic ranges and quantization uncertainty
-----------------------------------------------
Range (nT) Quantization (nT)
-----------------------------------------------
1. +/- 8.8 +/- .0022
2. +/- 26 +/- .0063
3. +/- 79 +/- .019
4. +/- 240 +/- .059
5. +/- 710 +/- .173
6. +/- 2100 +/- .513
7. +/- 6400 +/- 1.56
8. +/- 50,000 +/- 12.2
Processing
==========
Voyager EDR's undergo the following processing in order to produce
these 48 second averaged summary data:
* Read EDR
* Unpack header block (rec. id, s/c id, tel. mode, FDS counts,
data flags)
* Convert selected time tags to integer time (yy/ddd/hh:mm:ss.fff)
* Unpack sub-header block (MAG status words, plasma data)
* Unpack science block (MAG counts)
* Convert counts to gammas
* Apply sensor and boom alignment matrices
* Rotate (optional) 1.92 second averages while averaging detail
gammas to create 1.92 second averages
* Average 1.92 second data to 9.6 seconds, then 9.6 second data to
48 seconds
* Write Summary record
Counts are measured onboard using 12 bit words that may represent
values ranging from 0-4096. Integer counts are converted to magnetic
field units (gammas) by subtracting a zero offset, from the measured
MAG value and multiplying this difference by the sensitivity of the
instrument.
Data
====
The data files are given in ASCII, fixed field width, comma
delimited tables. The record structure is described in the following
table:
--------------------------------------------------------------------
48 Second System III (1965) Coordinates
--------------------------------------------------------------------
Column Type Description
--------------------------------------------------------------------
time a

Version 1.1
-----------
This version 1.1 data set replaces the version 1.0 data set
(DATA_SET_ID = VG1-J-MAG-4-9.60SEC) previously archived with PDS.
Changes to this version include the addition of data columns not
included in version 1.0, the modification of time format and flag
values, and upgrade of associated labels and catalog templates to
PDS version 3.2.
Data Set Overview
=================
This data set includes calibrated magnetic field data acquired by
the Voyager 1 Low Field Magnetometer (LFM) during the Jupiter
encounter. Coverage begins in the solar wind inbound to Jupiter and
continues past the last outbound bowshock crossing. The data are in
System III (1965) (SYS3) coordinates and have been averaged from the
1.92 second summary data to a 9.6 second sample rate. All magnetic
field measurements are given in nanoTesla (nT). The magnetic field
data are calibrated (see the calibration description included in the
Voyager 1 Magnetometer instrument catalog file for details).
Parameters
==========
The full LFM instrument sample rate is 1 sample per 0.06 seconds.
Full telemetry resolution 'detail' data must be obtained from the
instrument team. For this data set, the data have been resampled to
9.6 seconds from 1.92 second summary data. The 1.92 second data were
in turn resampled from the detail data.
The LFM has eight dynamic ranges. The instrument is designed switch
between dynamic ranges automatically depending upon the observed
magnetic field magnitude and fluctuations. Instrument digitization
uncertainty depends upon dynamic range as indicated in the following
table (from [BEHANNONETAL1977]).
-----------------------------------------------
LFM Dynamic ranges and quantization uncertainty
-----------------------------------------------
Range (nT) Quantization (nT)
-----------------------------------------------
1. +/- 8.8 +/- .0022
2. +/- 26 +/- .0063
3. +/- 79 +/- .019
4. +/- 240 +/- .059
5. +/- 710 +/- .173
6. +/- 2100 +/- .513
7. +/- 6400 +/- 1.56
8. +/- 50,000 +/- 12.2
Processing
==========
Voyager EDR's undergo the following processing in order to produce
these 9.6 second averaged summary data:
* Read EDR
* Unpack header block (rec. id, s/c id, tel. mode, FDS counts,
data flags)
* Convert selected time tags to integer time (yy/ddd/hh:mm:ss.fff)
* Unpack sub-header block (MAG status words, plasma data)
* Unpack science block (MAG counts)
* Convert counts to gammas
* Apply sensor and boom alignment matrices
* Rotate (optional) 1.92 second averages while averaging detail
gammas to create 1.92 second averages
* Average 1.92 second data to 9.6 seconds
* Write Summary record
Counts are measured onboard using 12 bit words that may represent
values ranging from 0-4096. Integer counts are converted to magnetic
field units (gammas) by subtracting a zero offset, from the measured
MAG value and multiplying this difference by the sensitivity of the
instrument.
Data
====
The data files are given in ASCII, fixed field width, comma
delimited tables. The record structure is described in the following
table:
--------------------------------------------------------------------
9.6 Second System III (1965) Coordinates
--------------------------------------------------------------------
Column Type Description
--------------------------------------------------------------------
time a23 spacecraft event time (UT) of the sample in the
format: yyyy-mm-ddThh:mm:ss.sss
sclk a12 spacecraft clock in the format:
MOD65536:MOD60:FDS-LINE
mag_id i1 magnetometer ID (1 = LFM, 2 = HFM)
Br f9.3 average of detail magnetic field R component in nT
Btheta f9.3 average of detail magnetic field Theta component in
nT
Bphi f9.3 average of detail magnetic field Phi component in

Data Set Overview
=================
Version 1.1
-----------
This version 1.1 data set replaces the version 1.0 data set
(DATA_SET_ID = VG1-J-PLS-5-ION-MOM-96.0SEC) previously
archived with the PDS.
Data Set Description
--------------------
This data set contains the best estimates of the total ion
density at Jupiter during the Voyager 1 encounter in the PLS
voltage range (10-5950 eV/Q). It is calculated using the
method of [MCNUTTETAL1981] which to first order consists of
taking the total measured current and dividing by the
collector area and plasma bulk velocity. This method is only
accurate for high mach number flows directly into the
detector, and may result in underestimates of the total
density of a factor of 2 in the outer magnetosphere. Thus
absolute densities should be treated with caution, but
density variations in the data set can be trusted. The low
resolution mode density is used before 1979 63 1300, after
this the larger of the high and low resolution mode densities
in a 96 sec period is used since the L-mode spectra often are
saturated. Corotation is assumed inside L=17.5, and a
constant velocity component of 200 km/s into the D cup is
used outside of this. These are the densities given in
[MCNUTTETAL1981] corrected by a factor of 1.209 (.9617) for
densities obtained from the side (main) sensor. This
correction is due to a better calculation of the effective
area of the sensors. Data format: column 1 is time
(yyyy-mm-ddThh:mm:ss.sssZ), column 2 is the moment density in
cm^-3. Each row has format (a24, 1x, 1pe9.2). Values of
-9.99e+10 indicate that the parameter could not be obtained
from the data using the standard analysis technique.
Additional information about this data set and the instrument
which produced it can be found elsewhere in this catalog. An
overview of the data in this data set can be found in
[MCNUTTETAL1981] and a complete instrument description can be
found in [BRIDGEETAL1977].
Processing Level Id : 5
Software Flag : Y
Parameters
==========
Ion Density
-----------
Sampling Parameter Name : TIME
Data Set Parameter Name : ION DENSITY
Sampling Parameter Resolution : 96.000000
Sampling Parameter Interval : 96.000000
Minimum Available Sampling Int : 96.000000
Data Set Parameter Unit : EV
Sampling Parameter Unit : SECOND
A derived parameter equaling the number of ions per unit
volume over a specified range of ion energy, energy/charge,
or energy/nucleon. Discrimination with regard to mass and or
charge state is necessary to obtain this quantity, however,
mass and charge state are often assumed due to instrument
limitations.
Many different forms of ion density are derived. Some are
distinguished by their composition (N+, proton, ion, etc.) or
their method of derivation (Maxwellian fit, method of
moments). In some cases, more than one type of density will
be provided in a single data set. In general, if more than
one ion species is analyzed, either by moment or fit, a total
density will be provided which is the sum of the ion
densities. If a plasma component does not have a Maxwellian
distribution the actual distribution can be represented as
the sum of several Maxwellians, in which case the density of
each Maxwellian is given.
Source Instrument Parameters
============================
Instrument Host ID : VG1
Data Set Parameter Name : ION DENSITY
Instrument Parameter Name : ION RATE
ION CURRENT
PARTICLE MULTIPLE PARAMETERS
Important Instrument Parameters : 1 (for all parameters)
Processing
==========
Processing History
------------------
Source Data Set ID : VG1-PLS
Software : MOMANAL
Product Data Set ID : VG1-J-PLS-5-ION-MOM-96.0SEC
Software 'MOMANAL'
------------------
Software

Data Set Overview
=================
Instrument P.I. : John D. Richardson
Data Supplier : John D. Richardson
Data sampling rate : 96 seconds
Data Set Start Time : 1979-03-13T00:01:43.491Z
Data Set Stop Time : 1979-03-24T23:20:06.519Z
This data set contains plasma parameters from Voyager 1
outbound from Jupiter from the magnetotail through the solar
wind. Fit and moment parameters are given; the fit parameters
assume a single, isotropic convected proton Maxwellian
distribution. Although magnetotail data is provided, these
data are unreliable; the density can be used as an upper limit
to the actual density. Solar wind data are also provided and
are reliable. These M mode data are the best data to use in
most regions of the magnetosheath. Magnetotail data in this
data set are included mainly to put the sheath data in context
and show magnetopause.
Parameters
==========
Data Set Parameter 'ION DENSITY'
--------------------------------
Data Set Parameter Name : ION DENSITY
Data Set Parameter Unit : CM**-3
Sampling Parameter Name : TIME
Sampling Parameter Unit : SECOND
Minimum Sampling Parameter : UNK
Maximum Sampling Parameter : UNK
Sampling Parameter Interval : UNK
Minimum Available Sampling Int : UNK
Noise Level : UNK
A derived parameter equaling the number of ions per unit
volume over a specified range of ion energy, energy/charge,
or energy/nucleon. Discrimination with regard to mass and or
charge state is necessary to obtain this quantity, however,
mass and charge state are often assumed due to instrument
limitations.
Many different forms of ion density are derived. Some are
distinguished by their composition (N+, proton, ion, etc.) or
their method of derivation (Maxwellian fit, method of
moments). In some cases, more than one type of density will
be provided in a single data set. In general, if more than
one ion species is analyzed, either by moment or fit, a total
density will be provided which is the sum of the ion
densities. If a plasma component does not have a Maxwellian
distribution the actual distribution can be represented as
the sum of several Maxwellians, in which case the density of
each Maxwellian is given.
Data Set Parameter 'ION THERMAL SPEED'
--------------------------------------
Data Set Parameter Name : ION THERMAL SPEED
Data Set Parameter Unit : KM/S
Sampling Parameter Name : TIME
Sampling Parameter Unit : SECOND
Minimum Sampling Parameter : UNK
Maximum Sampling Parameter : UNK
Sampling Parameter Interval : UNK
Minimum Available Sampling Int : UNK
Noise Level : UNK
A measure of the velocity associated with the temperature of
the ions. It is formally defined as the Ion Thermal Speed
squared equals two times K (Boltzmann's constant) times T
(temperature of ion) divided by M (ion mass). Each component
of a plasma has a thermal speed associated with it.
Data Set Parameter 'ION VELOCITY'
---------------------------------
Data Set Parameter Name : ION VELOCITY
Data Set Parameter Unit : KM/S
Sampling Parameter Name : TIME
Sampling Parameter Unit : SECOND
Minimum Sampling Parameter : UNK
Maximum Sampling Parameter : UNK
Sampling Parameter Interval : UNK
Minimum Available Sampling Int : UNK
Noise Level : UNK
A derived parameter giving the average speed and direction of
motion of a plasma or plasma component. The velocity can be
obtained by taking the first moment of the distribution
function or by simulating the observations with some known
distribution function, usually a Maxwellian, to the
distribution. Velocities are given in heliographic (RTN)
coordinates:
R is radially away from sun,
T is in plane of sun's equator and positive in the direction
of solar rotation,
N completes right-handed system.
Source Instrument Parameters
============================
Instrument Host ID : VG1
Data Set Parameter Name : ION DENSITY
Instrument Parameter Name : ION RATE
Important Instrument Parameters : 1
Instrument Host ID : VG1
Data Set Parameter Name : ION DENSITY
Instrument Parameter Name : ION CURRENT
Important Instrument Parameters : 1
Instrument Host ID : VG1
Data Set Parameter Name : ION VELOCITY
Instrument Parameter Name : ION CURRENT
Important Instrument Parameters : 1
Instrument Host ID : VG1
Data Set Parameter Name : ION THERMAL SPEED
Instrument Parameter Name : ION RATE
Important Instrument Parameters : 1
Instrument Host ID : VG1
Data Set Parameter Name : ION THERMAL SPEED
Instrument Parameter Name : ION CURRENT
Important Instrument Parameters : 1
Instrument Host ID : VG1
Data Set Parameter Name : ION DENSITY
Instrument Parameter Name : PARTICLE MULTIPLE PARAMETERS
Important Instrument Parameters : 1
Data Coverage
=============
Filename Records Start Stop
-------------------------------------------------------------------
T79072 10232 1979-03-13T00:01:43.491Z 1979-03-24T23:20:06.519Z

Spectrogram plots in GIF format derived from Voyager 1 Planetary Radio Astronomy (PRA) Highband receiver daily files
during Jupiter Encounter (1979-02-01 to 1979-04-13). These plots are available for both polarization channels and in both color and grayscale.
The color scale of these plots represent the electric field power spectral density in units of millibels.
Across the top of each spectrogram in the spacecraft and instrument name, the name of the binary data file
that was used to create this plot, the polarization channel (Left or Right) and the date in the format YYMMDD.
The data set provides 48 second resolution highband radio mean power data
in units of millibels. The high-band receiver consisted of 128 channels of
200 kHz bandwidth each, with center frequencies spaced at 307.2 kHz
intervals from 1.2 MHz to 40.4 MHz. The highband receiver was designed
especially for the observation of Jovian decametric radio emissions. The
PRA radiometer was usually operated routinely in the so-called POLLO sweeping
mode, in which all 198 frequency channels of the high- and low-band receivers
together were swept in 6 sec, dwelling at each channel for 25 msec. From one
step to the next in the channel switching sequence, the antenna polarization
sense was reversed, i.e., was changed from RH to LH or vice versa. Thus the
time required for making a measurement of both the RH and LH intensity
components at both senses of elliptical polarization at a given frequency was
12 sec. The data consists of successive averages of 4 pairs of RH and LH
intensity measurements, each average spanning an interval of 48 sec.
The data are calibrated and are given in units of
'millibels' which is 1000 times the log of the received power.
Zero millbels corresponds to approximately 1.4 x 10^-21 W m^-2
Hz^-1, however, this value is never seen in practice. The
minimum values detected, which includes receiver internal and
spacecraft generated noise, are about 2300 to 2400 millibels,
or about 3.5 x 10^-19 W m^-2 Hz^-1; even higher values are seen
at the very lowest frequencies.
Note:
The polarization indicated is the received polarization, not
necessarily the emitted polarization. Correct interpretation of
the received polarization depends on the antenna plane
orientation relative to the radio source. A good description of
this concept can be found in
Leblanc Y., Aubier M. G., Ortega-Molina A.,
Lecacheux A., 1987, J.Geophys. Res. 92, 15125 and in
Wang, L. and Carr, T.D.,
Recalibration of the Voyager PRA antenna for polarization sense
measurement, Astron. Astrophys., 281, 945-954, 1994. and references therein.

Voyager 1 Planetary Radio Astronomy (PRA) Highband receiver daily files
during Jupiter Encounter (1979-02-01 to 1979-04-13). Associated with these binary data are a series of quick-look GIF spectrogram plots created using the binary data. The plots are available for both polarization channels. These binary data were also converted into IDL save sets.
The data set provides 48 second resolution highband radio mean power data
in units of millibels. The high-band receiver consisted of 128 channels of
200 kHz bandwidth each, with center frequencies spaced at 307.2 kHz
intervals from 1.2 MHz to 40.4 MHz. The highband receiver was designed
especially for the observation of Jovian decametric radio emissions. The
PRA radiometer was usually operated routinely in the so-called POLLO sweeping
mode, in which all 198 frequency channels of the high- and low-band receivers
together were swept in 6 sec, dwelling at each channel for 25 msec. From one
step to the next in the channel switching sequence, the antenna polarization
sense was reversed, i.e., was changed from RH to LH or vice versa. Thus the
time required for making a measurement of both the RH and LH intensity
components at both senses of elliptical polarization at a given frequency was
12 sec. The data consists of successive averages of 4 pairs of RH and LH
intensity measurements, each average spanning an interval of 48 sec.
The format of these binary data files is as follows:
file separation variable
year, month, day information
millisecond decimal value of the day
Integer array (128,2) for 128 left and right channels (NOTE 128 channels for Hi-band; 70 channels for Lo-band)
file separation variable
There is an IDL program that reads these files into an IDL-format save set. See Information URL for a link to this file.
The data are calibrated and are given in units of
'millibels' which is 1000 times the log of the received power.
Zero millbels corresponds to approximately 1.4 x 10^-21 W m^-2
Hz^-1, however, this value is never seen in practice. The
minimum values detected, which includes receiver internal and
spacecraft generated noise, are about 2300 to 2400 millibels,
or about 3.5 x 10^-19 W m^-2 Hz^-1; even higher values are seen
at the very lowest frequencies.
Note:
The polarization indicated is the received polarization, not
necessarily the emitted polarization. Correct interpretation of
the received polarization depends on the antenna plane
orientation relative to the radio source. A good description of
this concept can be found in
Leblanc Y., Aubier M. G., Ortega-Molina A.,
Lecacheux A., 1987, J.Geophys. Res. 92, 15125 and in
Wang, L. and Carr, T.D.,
Recalibration of the Voyager PRA antenna for polarization sense
measurement, Astron. Astrophys., 281, 945-954, 1994. and references therein.

(Description based on material from VG1_PRA_JUP_HRES_DS.CAT)
Voyager 1 Radio Astronomy (PRA) data from the Jupiter encounter (1979-01-06 to 1979-04-13).
The data set provides 6 second high resolution lowband radio mean power data. The data
are provided for 70 instrument channels, covering 1.2 to 1326.0 kHz.
This data set (VG1-J-PRA-3-RDR-LOWBAND-6SEC-V1.0) contains
data acquired by the Voyager-1 Planetary Radio Astronomy (PRA)
instrument during the Jupiter encounter. The bounding time
interval set for most Voyager 1 Jupiter PDS data sets is the
Voyager project defined 'far encounter' mission phase boundary
(1979-02-28 to 1979-03-22). Since, however, the PRA instrument
is able to observe planetary phenomenon at much larger ranges
than other fields and particles experiments, this boundary is
artificial with respect to PRA. Hence, PRA lowband data
provided here cover the entire Jupiter Encounter Phase
(1979-01-06 to 1979-04-13). Data from beyond the far encounter
interval is contained in the cruise data archive which is
available from the NSSDC.
VG1-J-PRA-3-RDR-LOWBAND-6SEC-V1.0 contains data at the highest
time resolution possible during normal operations. The normal
mode of PRA operations during the planetary encounters was to
sweep through the two radio receiver bands, high band (40.5 to
1.5 MHz in 128 channels spaced 0.3072 MHz apart) and low band
(1326.0 to 1.2 kHz in 70 channels spaced 19.2 kHz apart) in a
period of 6 seconds. The receivers measured, on alternate
samples, the left hand circular and right hand circular (radio
definition) power.
Measured Parameters
===================
The data here are from the low frequency receiver band and are
'packaged' into spacecraft major frame records. Each major
frame is 48 seconds long or eight sweeps through the PRA
receiver. The data are calibrated and are given in units of
'millibels' which is 1000 times the log of the received power.
Zero millbels corresponds to approximately 1.4 x 10^-21 W m^-2
Hz^-1, however, this value is never seen in practice. The
minimum values detected, which includes receiver internal and
spacecraft generated noise, are about 2300 to 2400 millibels,
or about 3.5 x 10^-19 W m^-2 Hz^-1; even higher values are seen
at the very lowest frequencies.
The data format is ASCII and consists of a time indicator
followed by an array containing the eight low band sweeps. Time
is spacecraft event time (SCET) which is basically universal
time at the spacecraft. Specifically, time is in the form of
YYMMDD and seconds into YYMMDD. Both are written as I6.
Example: July 1, 1979 at 12 hours SCET would be 790701, 43200.
The seconds correspond, to the nearest second, to the start of
the sweep (which occurs in PRA high band). The first value in
low band (1326.0 kHz) occurs some 3.9 seconds after this time
and samples at successively lower frequencies are spaced 0.03
seconds apart. Only one time is given for the entire major
frame, thus the start of each sweep is the time given plus 6
times the sweep number minus 1 (i.e., 0 through 7).
The data array is dimensioned as 71 X 8 and written as I4
format (i.e. 568I4). The '8' corresponds to the eight PRA
sweeps. The lowest 68 of the 70 low band channels (1287.6
to 1.2 kHz) are in positions 2-69. Positions 70-71 should be
ignored. Missing or bad data values are set to zero. In
position 1 of each sweep is a status word where the 12 least
significant bits have used, although not all 12 have meaning
for PRA low band. Numbering those bits 0 for least significant
to 11 for most significant, the bits that have meaning are as
follows:
bit
0: 15 dB attenuator in use when equal to 1
1: 30 dB attenuator in use when equal to 1
2: 45 dB attenuator in use when equal to 1
9,10 (together): polarization of first channel sampled (1326.0
kHz) according to the scheme:
+---------------------------+
| | |value bit|
| | | 10= |
| | | 0 | 1 |
|value bit 9=| 0 | R | L |
| | 1 | L | R |
+---------------------------+
Polarization at successively lower frequencies is opposite to
the frequency above it, i.e. either a LRLR or an RLRL pattern.
Successive 6-second sweeps start on the opposite polarization
as the previous sweep as indicated in the status bits. Note
that this polarization is the received polarization, not
necessarily the emitted polarization. Correct interpretation of
the received polarization depends on the antenna plane
orientation relative to the radio source. A good description of
this concept can be found in Leblanc Y., Aubier M. G., Ortega-Molina A.,
Lecacheux A., 1987, J.Geophys. Res. 92, 15125 and in Wang, L. and Carr, T.D.,
Recalibration of the Voyager PRA antenna for polarization sense
measurement, Astron. Astrophys., 281, 945-954, 1994. and references therein.
Missing or bad data values are set to zero. If the status word
is zero, any data in that receiver sweep should be discarded.
Data Coverage
=============
The data are stored as 4 ASCII tables (.TAB), each accompanied with a PDS
label file (.LBL) which describes properties of the data file. Data
cover the following time intervals:
Volume ID: VGPR_1201
+------------------------------------------------------------------------+
| Filename |Records| Start | Stop |
|------------------------------------------------------------------------|
| PRA_I.TAB | 35569| 1979-01-06T00:00:34.000Z | 1979-01-30T23:59:47.000Z|
| PRA_II.TAB| 39493| 1979-01-31T00:00:35.000Z | 1979-02-25T23:59:47.000Z|
|PRA_III.TAB| 41371| 1979-02-26T00:00:35.000Z | 1979-03-22T23:59:56.000Z|
| PRA_IV.TAB| 24587| 1979-03-23T00:00:44.000Z | 1979-04-13T23:59:08.000Z|
+------------------------------------------------------------------------+
Confidence Level Overview
=========================
The accuracy of calibration in the PRA low band is
approximately 2 dB, except at frequencies below 100 kHz where
it is somewhat worse. Interference from the Voyager power
subsystem is a major problem to the PRA instrument, affecting
many of the 70 low band channels. This interference manifests
itself by abrupt changes in background levels. Some channels,
notably 136 and 193 kHz, are almost always affected, whereas,
others are only affected for short intervals. Usually, this
interference is only a problem when the natural signals are
weak.
Additional information associated with this data set is available in the
following files:
+-----------------------------------------------------------------------------------------------------------------------------------+
| file | contents |
| http://ppi.pds.nasa.gov/ditdos/download?id=pds://PPI/VGPR_1201/CATALOG/VG1_PRA1_INST.CAT |VG1 PRA instrument description |
| http://ppi.pds.nasa.gov/ditdos/download?id=pds://PPI/VGPR_1201/CATALOG/VG1_PRA_JUP_HRES_DS.CAT | data set description |
| http://ppi.pds.nasa.gov/ditdos/download?id=pds://PPI/VGPR_1201/CATALOG/PERSON.CAT | personnel information |
| http://ppi.pds.nasa.gov/ditdos/download?id=pds://PPI/VGPR_1201/CATALOG/REF.CAT |key reference description |
| http://ppi.pds.nasa.gov/ditdos/download?id=pds://PPI/VGPR_1201/DOCUMENT/INSTRUMENT |ASCII and HTML versions of the PRA|
| |investigation description paper |
+-----------------------------------------------------------------------------------------------------------------------------------+

Data Set Overview
=================
Instrument P.I. : James W. Warwick
Data Supplier : Michael L. Kaiser
Data sampling rate : 48 seconds
Data Set Start Time : 1979-01-06T00:00:48.000Z
Data Set Stop Time : 1979-04-13T23:58:24.000Z
This data set consists of edited browse data derived from an
original data set obtained from the Voyager 1 Planetary Radio
Astronomy (PRA) instrument in the vicinity of Jupiter. Data
are provided for 70 instrument channels covering the range from
1.2 kHz to 1326 kHz in uniform 19.2 kHz steps, each 1 kHz wide.
Data are included for the period 1979-01-06 00:00:48 through
1979-04-13 23:58:24. In order to produce this data set from
the original raw PRA data, several steps have been taken:
1. The PRA operates in a variety of modes; data from modes in
which the receiver does not scan rapidly through its frequency
range have been removed;
2. The data have been calibrated as best we know how;
3. The data have been split into Left Hand Circular (LHC) and
Right Hand Circular (RHC) components;
4. The data have been binned into 48-second intervals.
Thus, values at a given channel are separated in time by an
increment of 48 seconds; each 48-second time interval has
associated with it a value for LHC polarization and one for RHC
polarization.
During data gaps, the entire record is absent from the data
set; that is, missing records have not been zero-filled or
otherwise marked. Bad data within a record is indicated by the
value zero, which cannot otherwise occur.
Each datum is returned as a 16-bit quantity; it represents the
mean power received in the given channel at the specified time
and polarization. The returned quantity is the value in mB
about a reference flux density. To convert a returned quantity
to flux, use the formula:
flux = 7.0x10^(-22)x10^(mB/1000) W m-2 Hz-1
Parameters
==========
Data Set Parameter 'RADIO WAVE SPECTRUM'
----------------------------------------
Data Set Parameter Name : RADIO WAVE SPECTRUM
Data Set Parameter Unit : MILLIBEL
Sampling Parameter Name : TIME
Sampling Parameter Unit : SECOND
Sampling Parameter Resolution : 0.001
Sampling Parameter Interval : 48
Minimum Available Sampling Int : 12
Noise Level : 2400
A set of derived parameters consisting of power fluxes at
various contiguous frequencies over a range of frequencies.
Millibels may be converted to watts/m**2/Hz by using the
formula for flux indicated above.
Source Instrument Parameters
============================
Instrument Host ID : VG1
Data Set Parameter Name : RADIO WAVE SPECTRUM
Instrument Parameter Name : WAVE FLUX DENSITY
ELECTRIC FIELD WAVEFORM
ELECTRIC FIELD COMPONENT
MAGNETIC FIELD COMPONENT
WAVE ELECTRIC FIELD INTENSITY
WAVE MAGNETIC FIELD INTENSITY
Important Instrument Parameters : 1 (for all parameters)
Data Coverage
=============
Filename Records Start Stop
-------------------------------------------------------------------
T790106 1565 1979-01-06T00:00:48.000Z 1979-01-06T23:59:12.000Z
T790107 1430 1979-01-07T00:01:36.000Z 1979-01-07T23:59:12.000Z
T790108 1454 1979-01-08T00:01:36.000Z 1979-01-08T23:59:12.000Z
T790109 1518 1979-01-09T00:01:36.000Z 1979-01-09T23:59:12.000Z
T790110 1517 1979-01-10T00:01:36.000Z 1979-01-10T23:59:12.000Z
T790111 1522 1979-01-11T00:01:36.000Z 1979-01-11T23:59:12.000Z
T790112 1460 1979-01-12T00:01:36.000Z 1979-01-12T23:25:36.000Z
T790113 298 1979-01-13T07:27:12.000Z 1979-01-13T23:58:24.000Z
T790114 1460 1979-01-14T00:00:48.000Z 1979-01-14T23:59:12.000Z
T790115 1535 1979-01-15T00:01:36.000Z 1979-01-15T23:59:12.000Z
T790116 1424 1979-01-16T00:01:36.000Z 1979-01-16T23:59:12.000Z
T790117 1442 1979-01-17T00:01:36.000Z 1979-01-17T23:59:12.000Z
T790118 1440 1979-01-18T00:01:36.000Z 1979-01-18T23:59:12.000Z
T790119 1371 1979-01-19T00:01:36.000Z 1979-01-19T23:59:12.000Z
T790120 1396 1979-01-20T00:01:36.000Z 1979-01-20T23:59:12.000Z
T790121 1540 1979-01-21T00:01:36.000Z 1979-01-21T23:58:24.000Z
T790122 1551 1979-01-22T00:00:48.000Z 1979-01-22T23:59:12.000Z
T790123 10

Data Set Overview
=================
This data set (VG1-J-PRA-3-RDR-LOWBAND-6SEC-V1.0) contains
data acquired by the Voyager-1 Planetary Radio Astronomy (PRA)
instrument during the Jupiter encounter. The bounding time
interval set for most Voyager 1 Jupiter PDS data sets is the
Voyager project defined 'far encounter' mission phase boundary
(1979-02-28 to 1979-03-22). Since, however, the PRA instrument
is able to observe planetary phenomenon at much larger ranges
than other fields and particles experiments, this boundary is
artificial with respect to PRA. Hence, PRA lowband data
provided here cover the entire Jupiter Encounter Phase
(1979-01-06 to 1979-04-13). Data from beyond the far encounter
interval is contained in the cruise data archive which is
available from the NSSDC.
VG1-J-PRA-3-RDR-LOWBAND-6SEC-V1.0 contains data at the highest
time resolution possible during normal operations. The normal
mode of PRA operations during the planetary encounters was to
sweep through the two radio receiver bands, high band (40.5 to
1.5 MHz in 128 channels spaced 0.3072 MHz apart) and low band
(1326.0 to 1.2 kHz in 70 channels spaced 19.2 kHz apart) in a
period of 6 seconds. The receivers measured, on alternate
samples, the left hand circular and right hand circular (radio
definition) power.
Measured Parameters
===================
The data here are from the low frequency receiver band and are
'packaged' into spacecraft major frame records. Each major
frame is 48 seconds long or eight sweeps through the PRA
receiver. The data are calibrated and are given in units of
'millibels' which is 1000 times the log of the received power.
Zero millbels corresponds to approximately 1.4 x 10^-21 W m^-2
Hz^-1, however, this value is never seen in practice. The
minimum values detected, which includes receiver internal and
spacecraft generated noise, are about 2300 to 2400 millibels,
or about 3.5 x 10^-19 W m^-2 Hz^-1; even higher values are seen
at the very lowest frequencies.
The data format is ASCII and consists of a time indicator
followed by an array containing the eight low band sweeps. Time
is spacecraft event time (SCET) which is basically universal
time at the spacecraft. Specifically, time is in the form of
YYMMDD and seconds into YYMMDD. Both are written as I6.
Example: July 1, 1979 at 12 hours SCET would be 790701, 43200.
The seconds correspond, to the nearest second, to the start of
the sweep (which occurs in PRA high band). The first value in
low band (1326.0 kHz) occurs some 3.9 seconds after this time
and samples at successively lower frequencies are spaced 0.03
seconds apart. Only one time is given for the entire major
frame, thus the start of each sweep is the time given plus 6
times the sweep number minus 1 (i.e., 0 through 7).
The data array is dimensioned as 71 X 8 and written as I4
format (i.e. 568I4). The '8' corresponds to the eight PRA
sweeps. The lowest 68 of the 70 low band channels (1287.6
to 1.2 kHz) are in positions 2-69. Positions 70-71 should be
ignored. Missing or bad data values are set to zero. In
position 1 of each sweep is a status word where the 12 least
significant bits have used, although not all 12 have meaning
for PRA low band. Numbering those bits 0 for least significant
to 11 for most significant, the bits that have meaning are as
follows:
bit
0: 15 dB attenuator in use when equal to 1
1: 30 dB attenuator in use when equal to 1
2: 45 dB attenuator in use when equal to 1
9,10 (together): polarization of first channel sampled (1326.0
kHz) according to the scheme:
value bit 10 =
0 1
value bit 9 = 0 R L
1 L R
Polarization at successively lower frequencies is opposite to
the frequency above it, i.e. either a LRLR or an RLRL pattern.
Successive 6-second sweeps start on the opposite polarization
as the previous sweep as indicated in the status bits. Note
that this polarization is the received polarization, not
necessarily the emitted polarization. Correct interpretation of
the received polarization depends on the antenna plane
orientation relative to the radio source. A good description of
this concept can be found in [LEBLANCETAL1987].
Missing or bad data values are set to zero. If the status word
is zero, any data in that receiver sweep should be discarded.
Data Coverage
=============
Filename Records Start Stop
-----------------------------------------------------------------------
Volume ID: VGPR_1201
PRA_I.TAB 35569 1979-01-06T00:00:34.000Z 1979-01-30T23:59:47.000Z
PRA_II.TAB 39493 1979-01-31T00:00:35.000Z 1979-02-25T23:59:47.000Z
PRA_III.TAB 41371 1979-02-26T00:00:35.000Z 1979-03-22T23:59:56.000Z
PRA_IV.TAB 24587 1979-03-23T00:00:44.000Z 1979-04-13T23:59:08.000Z

Data Set Overview
=================
This data set consists of electric field spectrum analyzer data
from the Voyager 1 Plasma Wave Subsystem obtained during the
entire mission. Data after 2013-12-31 will be added to the archive
on subsequent volumes. The data set encompasses all spectrum
analyzer observations obtained in the cruise mission phases
before, between, and after the Jupiter and Saturn encounter phases
as well as those obtained during the two encounter phases.
The Voyager 1 spacecraft travels from Earth to beyond 100 AU over
the course of this data set. To provide some guidance on when
some key events occurred during the mission, the following table
is provided.
Date Event
1977-09-05 Launch
1979-02-28 First inbound bow shock crossing at Jupiter
1979-03-22 Last outbound bow shock crossing at Jupiter
1980-11-11 First inbound bow shock crossing at Saturn
1980-11-16 Last outbound bow shock crossing at Saturn
1981-02-20 10 AU
1983-08-30 Onset of first major LF heliospheric radio event
1984-06-19 20 AU
1987-04-08 30 AU
1990-01-09 40 AU
1992-07-06 Onset of second major LF heliospheric radio event
1992-10-10 50 AU
1995-07-14 60 AU
1998-04-18 70 AU
2001-01-25 80 AU
2002-11-01 Onset of third major LF heliospheric radio event
2003-11-05 90 AU
2004-12-16 Termination shock crossing
2006-08-16 100 AU
2009-05-31 110 AU
2012-03-16 120 AU
2015-01-01 130 AU
Data Sampling
=============
This data set consists of full resolution edited, wave electric
field intensities from the Voyager 1 Plasma Wave Receiver spectrum
analyzer obtained during the entire mission. For each time
interval, a field strength is determined for each of the 16
spectrum analyzer channels whose center frequencies range from 10
Hertz to 56.2 kiloHertz and which are logarithmically spaced in
frequency, four channels per decade. The time associated with
each set of intensities (16 channels) is the time of the beginning
of the scan. The time between spectra in this data set vary by
telemetry mode and range from 4 seconds to 96 seconds. During
data gaps where complete spectra are missing, no entries exist in
the file, that is, the gaps are not zero-filled or tagged in any
other way. When one or more channels are missing within a scan,
the missing measurements are zero-filled. Data are edited but not
calibrated. The data numbers in this data set can be plotted in
raw form for event searches and simple trend analysis since they
are roughly proportional to the log of the electric field
strength. Calibration procedures and tables are provided for use
with this data set; the use of these is described below.
For the cruise data sets, the timing of samples is dependent upon
the spacecraft telemetry mode. In principle, one can determine
the temporal resolution between spectra simply by noting the
difference in time between two records in the files. In some
studies, more precise timing information is necessary. Here, we
describe the timing of the samples for the PWS low rate data as a
function of telemetry mode.
The PWS instrument uses two logarithmic compressors as detectors
for the 16-channel spectrum analyzer, one for the bottom (lower
frequency) 8 channels, and one for the upper (higher frequency) 8
channels. For each bank of 8 channels, the compressor
sequentially steps from the lowest frequency of the 8 to the
highest in a regular time step to obtain a complete spectrum. At
each time step, the higher frequency channel is sampled 1/8 s
prior to the lower frequency channel so that the channels are
sampled in the following order with channel 1 being the lowest
frequency channel (10 Hz) and 16 being the highest (56.2 kHz): 9,
1, 10, 2, 11, 3, ... 15, 7, 16, 8. The primary difference
between the various data modes is the stepping rate from one
channel to the next (ranging from 0.5 to 12 s, corresponding to
temporal resolutions between complete spectra of 4 s to 96 s).
In the following table, we present the hexadecimal id for the
various telemetry modes, the mode mnemonic ID, the time between
frequency steps, and the time between complete spectra. We also
provide the offset from the beginning of the instrument cycle (one
complete spectrum) identified as the time of each record's time
tag to the time of the sampling for the first high-frequency
channel (channel 9) and for the first low-frequency channel
(channel 1).
Time
Frequency Between High Freq. Low Freq.
MODE (Hex) MODE ID Step (s) Spectra (s) offset (s) offset (s)
01 CR-2 0.5 4.0 0.425 0.4325
02 CR-3 1.2 9.6 1.125 1.1325
03 CR-4 4.8 38.4 0.425 0.4325
04 CR-5 9.6 76.8 0.425 0.4325

Data Set Overview
=================
This data set consists of electric field waveform samples from
the Voyager 1 Plasma Wave Subsystem waveform receiver obtained
during the entire mission. Data after 2013-11-02 will be added to the
archive on subsequent volumes. The data set encompasses all
waveform observations obtained in the cruise mission phases
before, between, and after the Jupiter and Saturn encounter
phases as well as those obtained during the two encounter
phases.
The Voyager 1 spacecraft travels from Earth to beyond 100 AU over
the course of this data set. To provide some guidance on when
some key events occurred during the mission, the following table
is provided.
Date Event
1977-09-05 Launch
1979-02-28 First inbound bow shock crossing at Jupiter
1979-03-22 Last outbound bow shock crossing at Jupiter
1980-11-11 First inbound bow shock crossing at Saturn
1980-11-16 Last outbound bow shock crossing at Saturn
1981-02-20 10 AU
1983-08-30 Onset of first major LF heliospheric radio event
1984-06-19 20 AU
1987-04-08 30 AU
1990-01-09 40 AU
1992-07-06 Onset of second major LF heliospheric radio event
1992-10-10 50 AU
1995-07-14 60 AU
1998-04-18 70 AU
2001-01-25 80 AU
2002-11-01 Onset of third major LF heliospheric radio event
2003-11-05 90 AU
2004-12-16 Termination shock crossing
2006-08-16 100 AU
2009-05-31 110 AU
2012-03-16 120 AU
2015-01-01 130 AU
Data Sampling
=============
The waveform is sampled at 4-bit resolution through a bandpass
filter with a passband of 40 Hz to 12 kHz. 1600 samples are
collected in 55.56 msec (at a rate of 28,800 samples per second)
followed by a 4.44-msec gap. Each 60-msec interval constitutes
a line of waveform samples. The data set includes frames of
waveform samples consisting of up to 800 lines, or 48 seconds,
each. The telemetry format for the waveform data is identical
to that for images, hence the use of line and frame as
constructs in describing the form of the data.
Data Processing
===============
Because there is no direct method for calibrating these data and
because the raw format of packed, 4-bit samples is
space-efficient, these data are not processed for archiving.
The data may be plotted in raw form to show the actual waveform;
this is useful for studying events such as dust impacts on the
spacecraft. But the normal method of analyzing the waveform
data is by Fourier transforming the samples from each line to
arrive at an amplitude versus frequency spectrum. By stacking
the spectra side-by-side in time order, a frequency-time
spectrogram can be produced.
Data
====
The waveforms are collections of samples of the electric field
measured by the dipole electric antenna at a rate of 28,800
samples per second. The 4-bit samples provide sixteen digital
values of the electric field with a linear amplitude scale, but
the amplitude scale is arbitrary because of the automatic gain
control used in the waveform receiver. The instantaneous
dynamic range afforded by the 4 bit samples is about 23 dB, but
the automatic gain control allows the dominant signal in the
passband to be set at the optimum level to fit within the
instantaneous dynamic range. With the gain control, the overall
dynamic range of the waveform receiver is about 100 dB. The
automatic gain control gain setting is not returned to the
ground, hence, there is no absolute calibration for the data.
However, by comparing the waveform spectrum derived by Fourier
transforming the waveform to the spectrum provided by the
spectrum analyzer data, an absolute calibration may be obtained
in most cases.
Ancillary Data
==============
None
Coordinates
===========
The electric dipole antenna detects electric fields in a dipole
pattern with peak sensitivity parallel to the spacecraft x-axis.
However, no attempt has been made to correlate the measured
field to any particular direction such as the local magnetic
field or direction to a planet. This is because the spacecraft
remains in a 3-axis stabilized orientation almost continuously,
and these

Data Set Overview
=================
This data set consists of electric field spectrum analyzer data from
the Voyager 1 Plasma Wave Subsystem obtained during the entire
mission. Data after 2013-12-31 will be added to the archive on subsequent
volumes. The data set encompasses all spectrum analyzer
observations obtained in the cruise mission phases before, between,
and after the Jupiter and Saturn encounter phases as well as those
obtained during the two encounter phases.
The Voyager 1 spacecraft travels from Earth to beyond 90 AU over the
course of this data set. To provide some guidance on when some key
events occurred during the mission, the following table is provided.
Date Event
1977-09-05 Launch
1979-02-28 First inbound bow shock crossing at Jupiter
1979-03-22 Last outbound bow shock crossing at Jupiter
1980-11-11 First inbound bow shock crossing at Saturn
1980-11-16 Last outbound bow shock crossing at Saturn
1981-02-20 10 AU
1983-08-30 Onset of first major LF heliospheric radio event
1984-06-19 20 AU
1987-04-08 30 AU
1990-01-09 40 AU
1992-07-06 Onset of second major LF heliospheric radio event
1992-10-10 50 AU
1995-07-14 60 AU
1998-04-18 70 AU
2001-01-25 80 AU
2002-11-01 Onset of third major LF heliospheric radio event
2003-11-05 90 AU
2004-12-16 Termination shock crossing
2006-08-16 100 AU
2009-05-31 110 AU
2012-03-16 120 AU
2015-01-01 130 AU
Data Sampling
=============
This data set consists of average and peak wave electric field
intensities accumulated over 1-hour intervals from the Voyager 1
Plasma Wave Receiver spectrum analyzer obtained during the entire
mission. For each 1-hour time interval squares of the calibrated
electric field measurements obtained during each hour-long
interval in each of the 16 spectrum analyzer channels are summed
and then divided by the number of measurements. The square root
of the resulting value is obtained and stored as the average
electric field strength for the respective channel. During the
same hour-long interval, the maximum electric field strength
acquired in each of the 16 channels is also recorded and stored as
the peak electric field strength for the respective channel.
Hence, for each hour, an average and peak electric field spectrum
from 10 Hz to 56.2 kHz is obtained. The 16 spectrum analyzer
channels have center frequencies that range from 10 Hertz to 56.2
kiloHertz and are logarithmically spaced in frequency, four
channels per decade. The time associated with each peak and
average spectrum is the time of the beginning of the averaging
interval. Given variations in the sweep rate of the instrument
(from a minimum of 4 seconds/sweep to a maximum of 96
seconds/sweep) the maximum number of samples in an hour-long
interval can range from 900 to 38. Data gaps within the interval
can further reduce the number of samples.
During data gaps where complete spectra are missing, no entries
exist in the file, that is, the gaps are not zero-filled or tagged
in any other way.
Data Processing
===============
The spectrum analyzer data are a continuous (where data are
available) low resolution data set which provides wave intensity
as a function of frequency (16 log-spaced channels) and time (one
spectrum per time intervals ranging from 4 seconds to 96 seconds
in the full-resolution data set, depending on telemetry mode.)
This data set includes one-hour average and peak values for each
channel. The data are typically plotted as amplitude vs. time for
one or more of the channels in a strip-chart like display, or can
be displayed as a frequency-time spectrogram using a gray- or
color-bar to indicate amplitude. With only sixteen channels, it
is usually best to stretch the frequency axis by interpolating
from one frequency channel to the next either linearly or with a
spline fit. One must be aware if the frequency axis is stretched
that more resolution may be implied than is really present.
The measurements provided in the average and peak electric field
spectra included in this data set are in units of electric field
(volts/meter).
Spectral density units may be obtained by dividing the square of
the electric field value by the nominal frequency bandwidth of the
corresponding spectrum analyzer channel.
specdens = (efield(ichan))**2 / bandwidth(ichan)
Finally, power flux may be obtained by dividing the spectral
density by the impedance of free space in ohms:

Data Set Overview
=================
This data set consists of ASCII formatted plasma wave frequency
and electron plasma density measurements as measured by the Plasma
Waves Science instrument and calculated from the equations of cold
plasma theory. These frequency measurements were taken from
Voyager 1 electric field waveform samples from Voyager 1 Plasma
Wave Science (PWS) waveform receiver obtained during its Jupiter
flyby. The data set includes select measurements from spacecraft
event time (SCET) 1979-03-01T19:58:22.500Z to
1979-03-21T14:25:32.500Z. The data are separated into day files
and the individual data points are taken every 1-second. As will
be explained in more detail below, the frequency measurements and
therefore the density measurements in this data set are measured
from high-resolution wideband plasma wave spectra. To learn more
about these spectra and their specific submitted volumes, see the
Related PDS Products section in the AAREADME files found in the
root directory of this volume.
Parameters
==========
While the data essential to this volume are the electron plasma
densities, there are a number of other plasma parameters included
with this data. The data set consists of ASCII files with one
record per time step, occurring in 1-second increments. Each
record includes the time, magnetic field strength (obtained from
the Voyager 1 magnetometer), the electron cyclotron frequency (if
available), the frequency of the cutoff or resonance measured, a
code indicating the name of the frequency measured, the calculated
electron density, and a set of position coordinates for the
spacecraft at the time of the observation. Also included in each
record are the electron plasma frequency fpe, extraordinary mode
cutoff frequency fR=0, ordinary mode cutoff frequency fL=0, upper
hybrid resonance frequency fUH, and a quality index. One of these
four frequencies is just a copy of the measured cutoff or resonance
frequency while the remaining frequencies are calculated using the
magnetic field data and the equations of cold plasma theory.
Different files are used for each day.
Processing
==========
The ASCII density data files produced in this volume were derived
from measuring the characteristic frequencies from the local plasma.
The density was calculated from these data, along with cyclotron
frequency data derived from magnetic field data, using the equations
of cold plasma theory.
In order to measure these characteristic frequencies, this work
utilizes a new program that allows the operator to highlight the
general vicinity of the cutoff or resonance on a frequency-time
spectrogram. Then, an algorithm finds the cutoff or resonance in
the region and records the frequency at 1 second intervals. Hence,
the automated procedure has a high temporal resolution (1 second)
and requires a relatively low level of both manual effort and
subjective judgment by the operator.
There are two different algorithms used: one for cutoff detection
and one for resonance or peak detection. The cutoff detection
algorithm is controlled by a small number of parameters that can
be set by the operator. The first parameter is the cutoff level.
In determining possible cutoff candidates, the algorithm scans the
region highlighted by the operator and records two separate points,
one above the cutoff level and one below. The closer the two points
are, temporally, the steeper the slope will be. Therefore, the
operator can change the location of the cutoff level to manipulate
where the algorithm looks for cutoffs within the highlighted region
of interest. The next parameter is the slope magnitude, which
designates the minimum magnitude of the finite difference slope
where the cutoff must reside. The operator may raise the slope
level in order to scan only for sharp cutoffs, or lower it in order
to accommodate less steep slopes, depending on the quality of the
spectrum data. When there is more than one possible cutoff, the
detection program will display them as cutoff candidates. The
cutoff level, slope magnitude and cutoff candidates are displayed by
the program for viewing by the operator. While the algorithm
chooses the lowest frequency cutoff by default, the operator may
override the algorithm and choose any of the possible cutoffs to be
recorded.
While most of the characteristic frequencies are, by definition,
the cutoff of propagating wave modes, there are certain
circumstances when the characteristic frequency is denoted as the
peak of a wave mode in the spectrum. Because of this, there is an
algorithm specifically for resonance or peak detection. Many
spectra of interest to this study include Z-mode radiation, which
has a low-frequency cutoff at fL=0. Barbosa et al.
[BARBOSAETAL1990B] demonstrated that taking the peak of the Z-mode
as fL=0 yields the highest consistency in the determination of
fpe. Hence, when the Z-mode is enhanced, we utilize the peak
detection algorithm to identify fL=0 from which fpe and the
electron density can be derived. This algorithm can also be used
to determine fUH when an enhancement at that frequency is present
in the spectrum. In order to measure this resonance or spectral
peak, the peak detection algorithm fits a Gaussian curve to the
highest peak within the region specified by the program operator.
The algorithm then records the frequency of the Gaussian's peak
as the peak frequency in the spectrum. The algorithm displays
the spectrum and a darker line which is the Gaussian. Because
there may be noise which exhibits a large peak in the highlighted
spectrum, the spectrum is displayed along with the Gaussian curve
and a vertical line designating where the peak was measured.

Data Set Overview
=================
Version 1.1
-----------
This version 1.1 data set replaces the version 1.0 data set
(DATA_SET_ID = VG1-J-PWS-2-SA-4.0SEC) previously archived
with the PDS. Changes to this version include the upgrade of
the associated labels and templates to PDS version 3
compliance.
Data Set Description
--------------------
This data set consists of 4-second edited, wave electric
field intensities from the Voyager 1 Plasma Wave Receiver
spectrum analyzer obtained in the vicinity of the Jovian
magnetosphere. For each 4-second interval, a field strength
is determined for each of the 16 spectrum analyzer channels
whose center frequencies range from 10 Hertz to 56.2
kiloHertz and which are logarithmically spaced in frequency,
four channels per decade. The time associated with each set
of intensities (16 channels) is the time of the beginning of
the scan. During data gaps where complete 4-second spectra
are missing, no entries exist in the file, that is, the gaps
are not zero-filled or tagged in any other way. When one or
more channels are missing within a scan, the missing
measurements are zero-filled. Data are edited but not
calibrated. The data numbers in this data set can be plotted
in raw form for event searches and simple trend analysis
since they are roughly proportional to the log of the
electric field strength. Calibration procedures and tables
are provided for use with this data set; the use of these is
described below.
Use of Voyager PWS Calibration Tables
-------------------------------------
The Voyager PWS calibration table is given in an ASCII text
file named VG1PWSCL.TAB (for Voyager-1). This provides
information to convert the uncalibrated 'data number' output
of the PWS 16-channel spectrum analyzer to calibrated antenna
voltages for each frequency channel. Following is a brief
description of these files and a tutorial in their
application.
Descriptive headers have been removed from this file. The
columns included are IDN, ICHAN01, ICHAN02, ICHAN03, ICHAN04,
ICHAN05, ICHAN06, ... ICHAN16.
The first column lists an uncalibrated data number followed
by the corresponding value in calibrated volts for each of
the 16 frequency channels of the PWS spectrum analyzer. Each
line contains calibrations for successive data number values
ranging from 0 through 255. (Data number 0 actually
represents the lack of data since the baseline noise values
for each channel are all above that.)
A data analysis program may load the appropriate table into a
data structure and thus provide a simple look-up scheme to
obtain the appropriate voltage for a given data number and
frequency channel. For example, the following VAX FORTRAN
code may be used to load a calibration array for Voyager 1
PWS:
real*4 cal (16,0:255)
open ( unit=10, file='VG1PWSCL.TAB', status='old' )
do i=0,255
read (10,*) idn, (cal(ichan,i),ichan=1,16)
end do
close (10)
Then, given an uncalibrated data value idn for the frequency
channel ichan, the corresponding calibrated antenna voltage
would be given by the following array reference:
volts = cal (ichan, idn)
This may be converted to a wave electric field amplitude by
dividing by the effective antenna length in meters, 7.07 m.
That is:
efield = cal(ichan, idn) / 7.07
Spectral density units may be obtained by dividing the square
of the electric field value by the nominal frequency
bandwidth of the corresponding spectrum analyzer channel.
specdens = (cal(ichan,idn)/7.07)**2 / bandwidth(ichan)
Finally, power flux may be obtained by dividing the spectral
density by the impedance of free space in ohms:
pwrflux = (cal(ichan,idn)/7.07)**2/bandwidth(ichan) / 376.73
Of course, for a particular application, it may be more
efficient to apply the above conversions to the calibration
table directly.
The center frequencies and bandwidths of each PWS spectrum
analyzer channel for each Voyager spacecraft are given below:

Data Set Overview
=================
Instrument P.I. : Rochus E. Vogt
Data Supplier : National Space Science Data Center
Data sampling rate : variable (1 hr for FPHA data, 15 min.
for all others)
Data Set Start Time : 1979-07-03T00:00:00.000Z
Data Set Stop Time : 1979-08-03T23:45:00.000Z
(The following description has been excerpted from
[NSSDCCRS1979])
As its name implies, the Cosmic Ray Subsystem (CRS) was
designed for cosmic ray studies [STONEETAL1977B]. It consists
of two high Energy Telescopes (HET), four Low Energy
Telescopes (LET) and The Electron Telescope (TET). The
detectors have large geometric factors (~ 0.48 to 8 cm^2 ster)
and long electronic time constants (~ 24 [micro]sec) for low
power consumption and good stability. Normally, the data are
primarily derived from comprehensive ([Delta]E[1], [Delta]E[2]
and E) pulse-height information about individual events.
Because of the high particle fluxes encountered at Jupiter and
Saturn, greater reliance had to be placed on counting rates in
single detectors and various coincidence rates. In inter-
planetary space, guard counters are placed in anticoincidence
with the primary detectors to reduce the background from
high-energy particles penetrating through the sides of the
telescopes. These guard counters were turned off in the Jovian
magnetosphere when the accidental anticoincidence rate became
high enough to block a substantial fraction of the desired
counts. Fortunately, under these conditions the spectra were
sufficiently soft that the background, due to penetrating
particles, was small.
The data on proton and ion fluxes at Jupiter were obtained
with the LET. The thicknesses of individual solid-state
detectors in the LET and their trigger thresholds were chosen
such that, even in the Jovian magnetosphere, electrons made,
at most, a very minor contribution to the proton counting
rates [LUPTON&STONE1972]. Dead time corrections and accidental
coincidences were small (< 20%) throughout most of the
magnetotail, but were substantial (> 50%) at flux maxima
within 40 R[J] Of Jupiter. Data have been included in this
package for those periods when the corrections are less than
~ 50% and can be corrected by the user with the dead time
appropriate to the detector (2 to 25 [micro]sec). The high
counting rates, however, caused some baseline shift which may
have raised proton thresholds significantly. In the inner
magnetosphere, the L[2] counting rate was still useful because
it never rolled over. This rate is due to 1.8- to 13-MeV
protons penetrating L[1] (0.43 cm^2 ster) and > 9-MeV protons
penetrating the shield (8.4 cm^2 ster). For an E^-2 spectrum,
the two groups would make comparable contributions; but in the
magnetosphere, for the E^-3 to E^-4 spectrum above 2.5 MeV
[MCDONALDETAL1979], the contribution from protons penetrating
the shield would be only 3 to 14%.
The LET L[1]L[2]L[4] and L[1]L[2]L[3] coincidence-
anticoincidence rates give the proton flux between 1.8 and 8
MeV and 3 to 8 MeV with a small alpha particle contribution
(~10^-3). Corrections are required for dead time losses in
L[1], accidental L[1]L[2] coincidences and anticoincidence
losses from L[4]. Data are given only for periods when these
corrections are relatively small. In addition to the rates
listed in the table, the energy lost in detectors L[1], L[2]
and L[3] was measured for individual particles. For protons,
this covered the energy range from 0.42 to 8.3 MeV. Protons
can be identified positively by the [Delta]E vs. E technique,
their spectra obtained and accidental coincidences greatly
reduced. Because of telemetry limitations, however, only a
small fraction of the events could be transmitted, and
statistics become poor unless pulse-height data are averaged
over a period of one hour.
HET and LET detectors share the same data lines and pulse-
height analyzers; thus, the telescopes can interfere with one
another during periods of high counting rates. To prevent such
an interference and explore different coincidence conditions,
the experiment was cycled through four operating modes, each
192 seconds long. Either the HETs or the LETs were turned on
at a time. LET-D was cycled through L[1] only and L[1]L[2]
coincidence requirements. The TET was cycled through various
coincidence conditions, including singles from the front
detectors. At the expense of some time resolution, this
procedure permitted us to obtain significant data in the outer
magnetosphere and excellent data during the long passage
through the magnetotail region.
Some of the published results from this experiment required
extensive corrections for dead time, accidental coincidences
and anticoincidences ([VOGTETAL1979A], [VOGTETAL1979B];
[SCHARDTETAL1981]; [GEHRELS1981]). These corrections can be
applied only on a case-by-case basis after a careful study of
the environment and many self-consistency checks. They cannot
be applied on a systematic basis and we have no computer
programs to do so; therefore, data from such periods are not
included in the Data Center submission. The scientists on the
CRS team will, however, be glad to consider special requests
if the desired information can be extracted from the data.
Description of the Data

Data Set Overview
=================
Version 1.1
-----------
The SEDR based data provided as part of this data set were
originally reviewed and archived with the NSSDC and PDS as
version 1.0 (DATA_SET_ID = VG2-J-POS-4-48.0SEC). Version 1.1
includes additional columns not present in the previous
version, 96 second rather than 48 second time samples, times
converted to 'PDS Style' or 'Zulu time', and upgrading of PDS
labels and templates to version 3.4. The SPICE based data that
are also part of this data set were not previously archived
with the PDS. This version 1.1 data set replaces previously
archived versions.
Data Set Description
--------------------
This data set consists of Voyager 2 Jupiter encounter
ephemeris data in System III (1965) left handed coordinates
covering the period 1979-07-05 to 1979-08-12. Two versions,
both covering the same time period, but containing slightly
different data, are provided. One version was generated by the
Voyager MAG team from Voyager 2 SEDR, the other by the PDS/PPI
node using the VG2_JUP.BSP and PCK00003.TCP SPICE kernels.
Due to inaccuracies in Voyager SEDR, as well as changes in the
values of some key parameters (e.g. Jovian radius) the timing
is improved for the SPICE generated data. However, since much
of the original analysis was based upon the SEDR generated
ephemeris, this data has been included as well.
SEDR generated ephemeris
------------------------
Instrument P.I. : N/A
Data Supplier : NSSDC
Data sampling rate : 96 seconds
Data Set Start Time : 1979-07-05T00:00:47.269Z
Data Set Stop Time : 1979-08-12T16:54:20.608Z
SPICE generated ephemeris
-------------------------
Instrument P.I. : N/A
Data Supplier : S. Joy
Data sampling rate : 48 seconds
Data Set Start Time : 1979-07-05T00:00:47.269Z
Data Set Stop Time : 1979-08-12T16:55:08.608Z
Parameters
==========
SEDR generated ephemeris
------------------------
PARAMETER RESOLUTION/ DESCRIPTION
NAME UNITS
time 96.0 Sec time of the sample (UT) in the format
yyyy-mm-ddThh:mm:ss.sssZ
m65536 counts spacecraft clock counts
mod60 counts
fds_line counts
sc_x R[J] jovicentric (System III) cartesian
sc_y R[J] cartesian position vectors: X, Y, and
sc_z R[J] Z
vel_x km/s jovicentric X, Y, and Z spacecraft
vel_y km/s velocity components
vel_z km/s
sc_r R[J] jovicentric (System III) spherical
sc_lat degrees coordinates position vectors: range,
sc_lon degrees latitude, and longitude
CartSys3_to_SphSys3 cartesian system III to spherical
system III coordinates rotation matrix
containing 9 1pe15.8 elements
SC_to_CartSys3 payload (spacecraft) to cartesian
system III coordinates rotation matrix
containing 9 1pe15.8 elements
SC_to_SphSys3 payload (spacecraft) to spherical
system III coordinates rotation matrix
containing 9 1pe15.8 elements
SPICE generated ephemeris
-------------------------
PARAMETER RESOLUTION/ DESCRIPTION
NAME UNITS
time 48.0 Sec time of the sample (UT) in the
format yyyy-mm-ddThh:mm:ss.sssZ
R AU jovicentric (System III 1965)
LAT degrees spherical coordinates position
LON degrees range, latitude, and longitude
LocTime hours angular separation between the
meridian containing the sun and the

Data Set Description
====================
Version 1.1
-----------
This version 1.1 data set replaces the version 1.0 data set
(DATA_SET_ID = VG2-J-LECP-4-15MIN) previously archived with
the PDS. Data records from the version 1.0 data set provided
data for each of 8 sectors, plus the average for all sectors
in a separate record for each channel. This resulted in 9
repeated times per channel. Data records for the version 1.1
data set provide all data for a given channel and time period
(8 sectors, plus the average for all sectors) in a single
record. Other changes to this version include upgrading of the
associated labels and templates to PDS version 3.4 compliance,
modification of the time formats and flag values.
Data Set Description
--------------------
This data set consists of resampled data from the Low Energy
Charged Particle (LECP) experiment on Voyager 2 while the
spacecraft was in the vicinity of Jupiter. This instrument
measures the intensities of in-situ charged particles (>26 keV
electrons and >30 keV ions) with various levels of
discrimination based on energy, mass species, and angular
arrival direction. A subset of almost 100 LECP channels are
included with this data set. The LECP data are globally
calibrated to the extent possible (see below) and they are
time averaged to about 15 minute time intervals with the exact
beginning and ending times for those intervals matching the
LECP instrumental cycle periods (the angular scanning periods).
The LECP instrument has a rotating head for obtaining angular
anisotropy measurements of the medium energy charged particles
that it measures. The cycle time for the rotation is variable,
but during encounters it is always faster than 15 minutes.
Thus, the full angular anisotropy information is preserved with
this data. The data is in the form of 'rate' data which has not
been converted to the usual physical units. The reason is that
such a conversion would depend on uncertain determinations such
as the mass species of the particles and the level of
background. Both mass species and background are generally
determined from context during the study of particular regions.
To convert 'rate' to 'intensity' for a particular channel one
performs the following tasks: 1) Decide on the level of
background contamination and subtract that off the given rate
level. Background is to be determined from context and from
making use of sector 8 rates (sector 8 has a 2 mm Al shield
covering it). 2) Divide the background corrected rate by the
channel geometric factor and by the energy bandpass of the
channel. The geometric factor is found in entry
'CHANNEL_GEOMETRIC_FACTOR' as associated with each channel
'CHANNEL_ID'. To determine the energy bandpass, one must
judge the mass species of the of the detected particles (for
ions but not for electrons). The energy band passes are given
in entries 'MINIMUM_INSTRUMENT_PARAMETER' and
'MAXIMUM_INSTRUMENT_PARAMETER' in table 'FPLECPENERGY', and
are given in the form 'energy/nucleon'. For channels that
begin their names with the designations 'CH' these bandpasses
can be used on mass species that are accepted into that
channel (see entries 'MINIMUM_INSTRUMENT_PARAMETER' AND
'MAXIMUM_INSTRUMENT_PARAMETER' in table 'FPLECPCHANZ', which
give the minimum and maximum 'Z' value accepted -- these
entries are blank for electron channels). For other channels
the given bandpass refers only to the lowest 'Z' value
accepted. The and passes for other 'Z' values are not all
known, but some are given in the literature (e.g.
[KRIMIGISETAL1979A]). The final product of these instructions
will be the particle intensity with the units:
counts/(cm^2 str sec keV).
Parameters
==========
Electron Rate
-------------
Sampling Parameter Name : TIME
Data Set Parameter Name : ELECTRON RATE
Sampling Parameter Resolution : 15.000000
Sampling Parameter Interval : 15.000000
Data Set Parameter Unit : COUNTS/SECOND
Noise Level : 0.000000
Sampling Parameter Unit : MINUTE
A measured parameter equaling the number of electrons hitting
a particle detector per specified accumulation interval. The
counted electrons may or may not be discriminated as to their
energies (e.g. greater than E1, or between E1 and E2).
Ion Rate
--------
Sampling Parameter Name : TIME
Data Set Parameter Name : ION RATE
Sampling Parameter Resolution : 15.000000
Sampling Parameter Interval : 15.000000
Data Set Parameter Unit : COUNTS/SECOND
Noise Level : 0.000000
Sampling Parameter Unit : MINUTE
A measured parameter equaling the number of ions striking a
particle detector per specified accumulation interval. The
counted ions may or may not be discriminated as to their
energies (e.g. energy/nucleon or energy/charge between E1 and
E2 or greater than E1) and/or as to their ion composition
(atomic number Z or mass number greater than Z1 or M1, or
between Z1 and z2 or M1 and M2).
Source Instrument Parameters
============================
Instrument Host ID : VG2
Data Set Parameter Name : ION RATE
Instrument Parameter Name : ION RATE
Important Instrument Parameters : 1
Instrument Host ID : VG2
Data Set Parameter Name : ELECTRON RATE
Instrument Parameter Name : ELECTRON RATE
Important Instrument Parameters : 1
Processing
==========
Processing Level Id : 4
Software Flag : Y
Processing Start Time : 1988-08-01
Processing History
------------------
Source Data Set ID : VG2-J-LECP-2-
Software : PFAT:VGER
Product Data Set ID : VG2-J-LECP-4-15MIN
Software 'PFAT:VGER'
--------------------
Software Name : PFAT:VGER
Software Type : PIN
Software Release Date : N/A
Node ID : N/A
Cognizant Engineer : N/A
Software Access Description : N/A
Data Coverage
=============
Filename Records Start Stop
-------------------------------------------------------------------
Volume ID: VG_1502
SECTOR.TAB 64944 1979-07-02T07:35:11.000 1979-08-03T23:30:21.000
SECTOR_SUMMARY.TAB 784 1979-07-02T07:00:00.000
1979-08-03T22:00:00.000

Data Set Overview
=================
Version 1.1
-----------
This version 1.1 data set replaces the version 1.0 data set
(DATA_SET_ID = VG2-J-MAG-4-48.0SEC) previously archived with
the PDS. Changes to this version include the addition of data
columns not included in version 1.0, the modification of time
format and flag values, and upgrade of associated labels and
catalog templates to PDS version 3.4.
Data Set Description
--------------------
This data set includes Voyager 2 Jupiter encounter
magnetometer data from the Low Field Magnetometer (LFM)
resampled at a 48 second sample rate. The data are given in
Jovicentric System III right handed coordinates and have been
averaged from the 60 ms instrument sample rate to a 48 second
resampled rate. Ephemeris data, provided in 96 second sampled
System III (1965) coordinates, have been merged into the data
files for this data set. The ephemeris data, generated from
Voyager 2 SEDR and provided by the Voyager MAG Team, are part
of the data set VG2-J-POS-6-SUMM-S3COORDS-V1.1. The position
vectors for times at which ephemeris is not provided have been
flagged.
The data set consists of the following columns: 1) UT of the
sample in the format yyyy-mm-ddThh:mm:ss.sssZ, 2-4) spacecraft
clock (m65536, mod60, fds-line), 5) magnetometer id (1 = LFM,
2 = HFM), 6) Br radial (Jupiter to spacecraft) B-field
component, 7) Btheta (North/South system III B-field
component, positive southward), 8) Bphi (azimuthal system III
B-field component, positive eastward), 9) Bmag (magnitude of
the averaged components), 10) avg_Bmag (average of the
magnetic field magnitudes), 11) delta (latitude =
arcsin(Btheta/Bmag)), 12) lambda (longitude = 180. -
atan(Bphi/-Br)), 13-15) rms vectors, 16) sc_r (Jupiter to
spacecraft range), 17) sc_lat (jovicentric latitude, positive
northward), 18) sc_lon (jovicentric east longitude, system III
1965) 19) npts (number of points in average), 20) data flag -
a flag value that indicates either software error or
spacecraft hardware interference reduced confidence in this
record (flag value of 1 is bad, 0 is good or unchecked). All
magnetic field observations are measured in nanoTesla. The
coordinate system for this data set is System (1965) III. All
of the magnetic field data are calibrated (see the instrument
calibration description for more details). The Jupiter System
III coordinate system is defined in [DESSLER1983] and the
reference documents for this data set are: [NESSETAL1979A],
[LEPPINGETAL1981], [CONNERNEYETAL1981], [BEHANNONETAL1981].
For more information regarding the ephemeris data, please
refer to the data set catalog file for the data set
VG2-J-POS-6-SUMM-S3COORDS-V1.1.
These data a provided in a conventional, right handed,
spherical coordinate system with vectors R, Theta, and Phi.
This system is sometimes referred to as System III (1965)
right handed coordinates. The the magnetic field vectors are:
BR - radial B-field component (along the Jupiter to
spacecraft line) positive away from Jupiter
BTHETA - North/South (system III) B-field component,
positive southward
BPHI - azimuthal (system III) B-field component, positive
eastward
System III (1965) spherical coordinates, the system in which
the ephemeris data are expressed, is a jovicentric left handed
system defined such that longitude increases with time as
viewed by a stationary remote observer.
R Jupiter to spacecraft range (positive away from
Jupiter)
LAT completes the left handed, orthogonal set
LON System III (1965) east longitude (with longitude
increasing eastward from a specific jovian prime
meridian)
Processing Level Id : 4
Software Flag : Y
Processing Start Time : 1988-09-21
Parameters
==========
Sampling Parameter Name : TIME
Data Set Parameter Name : MAGNETIC FIELD VECTOR
Sampling Parameter Resolution : 48.000000
Minimum Sampling Parameter : 19770820120000.000000
Maximum Sampling Parameter : UNK
Sampling Parameter Interval : 48.000000
Minimum Available Sampling Int : 0.060000
Data Set Parameter Unit : NANOTESLA
Noise Level : 0.006000
Sampling Parameter Unit : SECOND
PARAMETER RESOLUTION DESCRIPTION
NAME (UNITS)
time 48 Sec time of the sample (UT) in the
format yyyy-mm-ddThh:mm:ss.sssZ.

Data Set Overview
=================
Version 1.1
-----------
This version 1.1 data set replaces the version 1.0 data set
(DATA_SET_ID = VG2-J-PLS-5-ION-MOM-96.0SEC) previously
archived with the PDS. This data set was given a new DATA_SET_ID
and intentionally marked as V1.0.
Data Set Description
--------------------
This data set contains the best estimates of the total ion
density from Voyager 2 at Jupiter in the PLS voltage range
(10-5950 eV/Q). It is calculated using the method of
[MCNUTTETAL1981] which to first order consists of taking the
total measured current and dividing by the collector area and
plasma bulk velocity. This method is only accurate for high
mach number flows directly into the detector, and may result
in underestimates of the total density of a factor of 2 in the
outer magnetosphere. Thus absolute densities should be treated
with caution, but density variations in the data set can be
trusted. The low resolution mode density is used at all times
except day 190 2100-2200 when the larger of the high and low
resolution mode densities in a 96 sec period is used.
Corotation is assumed inside L=17.5, and a constant velocity
component of 200 km/s into the D cup is used outside of this.
These are the densities given in the [MCNUTTETAL1981] paper
corrected by a factor of 1.209 (.9617) for densities obtained
from the side (main) sensor. This correction is due to a
better calculation of the effective area of the sensors. Data
format: column 1 is time (yyyy-mm-ddThh:mm:ss.sssZ), column 2
is the moment density in cm^-3. Each row has format (a24, 1x,
1pe9.2). Values of -9.99e+10 indicate that the parameter could
not be obtained from the data using the standard analysis
technique. Additional information about this data set and the
instrument which produced it can be found elsewhere in this
catalog. An overview of the data in this data set can be found
in [MCNUTTETAL1981] and a complete instrument description can
be found in [BRIDGEETAL1977].
Processing Level Id : 5
Software Flag : Y
Parameters
==========
Ion Density
-----------
Sampling Parameter Name : TIME
Data Set Parameter Name : ION DENSITY
Sampling Parameter Resolution : 96.000000
Sampling Parameter Interval : 96.000000
Minimum Available Sampling Int : 96.000000
Data Set Parameter Unit : CM^-3
Sampling Parameter Unit : SECOND
A derived parameter equaling the number of ions per unit
volume over a specified range of ion energy, energy/charge, or
energy/nucleon. Discrimination with regard to mass and or
charge state is necessary to obtain this quantity, however,
mass and charge state are often assumed due to instrument
limitations.
Many different forms of ion density are derived. Some are
distinguished by their composition (N+, proton, ion, etc.) or
their method of derivation (Maxwellian fit, method of
moments). In some cases, more than one type of density will be
provided in a single data set. In general, if more than one
ion species is analyzed, either by moment or fit, a total
density will be provided which is the sum of the ion
densities. If a plasma component does not have a Maxwellian
distribution the actual distribution can be represented as the
sum of several Maxwellians, in which case the density of each
Maxwellian is given.
Source Instrument Parameters
============================
Instrument Host ID : VG2
Data Set Parameter Name : ION DENSITY
Instrument Parameter Name : ION RATE
ION CURRENT
PARTICLE MULTIPLE PARAMETERS
Important Instrument Parameters : 1 (for all parameters)
Processing
==========
Processing History
------------------

Data Set Overview
=================
Instrument P.I. : John D. Richardson
Data Supplier : John D. Richardson
Data sampling rate : 96 seconds
Data Set Start Time : 1979-07-23T23:42:34.541Z
Data Set Stop Time : 1979-08-10T04:04:57.070Z
This data set contains plasma parameters from Voyager 2
outbound from Jupiter from the magnetotail through the solar
wind. Fit and moment parameters are given; the fit parameters
assume a single, isotropic convected proton Maxwellian
distribution. Although magnetotail data is provided, these
data are unreliable; the density can be used as an upper limit
to the actual density. Solar wind data are also provided and
are reliable. These M mode data are the best data to use in
most regions of the magnetosheath. Magnetotail data in this
data set are included mainly to put the sheath data in context
and show magnetopause.
Parameters
==========
Data Set Parameter 'ION DENSITY'
--------------------------------
Data Set Parameter Name : ION DENSITY
Data Set Parameter Unit : CM**-3
Sampling Parameter Name : TIME
Sampling Parameter Unit : SECOND
Minimum Sampling Parameter : UNK
Maximum Sampling Parameter : UNK
Sampling Parameter Interval : UNK
Minimum Available Sampling Int : UNK
Noise Level : UNK
A derived parameter equaling the number of ions per unit
volume over a specified range of ion energy, energy/charge, or
energy/nucleon. Discrimination with regard to mass and or
charge state is necessary to obtain this quantity, however,
mass and charge state are often assumed due to instrument
limitations.
Many different forms of ion density are derived. Some are
distinguished by their composition (N+, proton, ion, etc.) or
their method of derivation (Maxwellian fit, method of
moments). In some cases, more than one type of density will be
provided in a single data set. In general, if more than one
ion species is analyzed, either by moment or fit, a total
density will be provided which is the sum of the ion
densities. If a plasma component does not have a Maxwellian
distribution the actual distribution can be represented as the
sum of several Maxwellians, in which case the density of each
Maxwellian is given.
Data Set Parameter 'ION THERMAL SPEED'
--------------------------------------
Data Set Parameter Name : ION THERMAL SPEED
Data Set Parameter Unit : KM/S
Sampling Parameter Name : TIME
Sampling Parameter Unit : SECOND
Minimum Sampling Parameter : UNK
Maximum Sampling Parameter : UNK
Sampling Parameter Interval : UNK
Minimum Available Sampling Int : UNK
Noise Level : UNK
A measure of the velocity associated with the temperature of
the ions. It is formally defined as the Ion Thermal Speed
squared equals two times K (Boltzmann's constant) times T
(temperature of ion) divided by M (ion mass). Each component
of a plasma has a thermal speed associated with it.
Data Set Parameter 'ION VELOCITY'
---------------------------------
Data Set Parameter Name : ION VELOCITY
Data Set Parameter Unit : KM/S
Sampling Parameter Name : TIME
Sampling Parameter Unit : SECOND
Minimum Sampling Parameter : UNK
Maximum Sampling Parameter : UNK
Sampling Parameter Interval : UNK
Minimum Available Sampling Int : UNK
Noise Level : UNK
A derived parameter giving the average speed and direction of
motion of a plasma or plasma component. The velocity can be
obtained by taking the first moment of the distribution
function or by simulating the observations with some known
distribution function, usually a Maxwellian, to the
distribution. Velocities are given in heliographic (RTN)
coordinates:
R is radially away from sun,
T is in plane of sun's equator and positive in the direction
of solar rotation,
N completes right-handed system.
Source Instrument Parameters
============================
Instrument Host ID : VG2
Data Set Parameter Name : ION DENSITY

Spectrogram plots in GIF format derived from Voyager 2 Planetary Radio Astronomy (PRA) Highband receiver daily files
during Jupiter Encounter (1979-06-01 to 1979-07-30). These plots are available for both polarization channels and in both color and grayscale.
The color scale of these plots represent the electric field power spectral density in units of millibels.
Across the top of each spectrogram in the spacecraft and instrument name, the name of the binary data file
that was used to create this plot, the polarization channel (Left or Right) and the date in the format YYMMDD.
The data set provides 48 second resolution highband radio mean power data
in units of millibels. The high-band receiver consisted of 128 channels of
200 kHz bandwidth each, with center frequencies spaced at 307.2 kHz
intervals from 1.2 MHz to 40.4 MHz. The highband receiver was designed
especially for the observation of Jovian decametric radio emissions. The
PRA radiometer was usually operated routinely in the so-called POLLO sweeping
mode, in which all 198 frequency channels of the high- and low-band receivers
together were swept in 6 sec, dwelling at each channel for 25 msec. From one
step to the next in the channel switching sequence, the antenna polarization
sense was reversed, i.e., was changed from RH to LH or vice versa. Thus the
time required for making a measurement of both the RH and LH intensity
components at both senses of elliptical polarization at a given frequency was
12 sec. The data consists of successive averages of 4 pairs of RH and LH
intensity measurements, each average spanning an interval of 48 sec.
The data are calibrated and are given in units of
'millibels' which is 1000 times the log of the received power.
Zero millbels corresponds to approximately 1.4 x 10^-21 W m^-2
Hz^-1, however, this value is never seen in practice. The
minimum values detected, which includes receiver internal and
spacecraft generated noise, are about 2300 to 2400 millibels,
or about 3.5 x 10^-19 W m^-2 Hz^-1; even higher values are seen
at the very lowest frequencies.
Note:
The polarization indicated is the received polarization, not
necessarily the emitted polarization. Correct interpretation of
the received polarization depends on the antenna plane
orientation relative to the radio source. A good description of
this concept can be found in
Leblanc Y., Aubier M. G., Ortega-Molina A.,
Lecacheux A., 1987, J.Geophys. Res. 92, 15125 and in
Wang, L. and Carr, T.D.,
Recalibration of the Voyager PRA antenna for polarization sense
measurement, Astron. Astrophys., 281, 945-954, 1994. and references therein.

Voyager 2 Planetary Radio Astronomy (PRA) Highband receiver daily files
during Jupiter Encounter (1979-06-01 to 1979-07-30). Associated with these binary data are a series of quick-look GIF spectrogram plots created using the binary data. The plots are available for both polarization channels. These binary data were also converted into IDL save sets.
The data set provides 48 second resolution highband radio mean power data
in units of millibels. The high-band receiver consisted of 128 channels of
200 kHz bandwidth each, with center frequencies spaced at 307.2 kHz
intervals from 1.2 MHz to 40.4 MHz. The highband receiver was designed
especially for the observation of Jovian decametric radio emissions. The
PRA radiometer was usually operated routinely in the so-called POLLO sweeping
mode, in which all 198 frequency channels of the high- and low-band receivers
together were swept in 6 sec, dwelling at each channel for 25 msec. From one
step to the next in the channel switching sequence, the antenna polarization
sense was reversed, i.e., was changed from RH to LH or vice versa. Thus the
time required for making a measurement of both the RH and LH intensity
components at both senses of elliptical polarization at a given frequency was
12 sec. The data consists of successive averages of 4 pairs of RH and LH
intensity measurements, each average spanning an interval of 48 sec.
The format of these binary data files is as follows:
file separation variable
year, month, day information
millisecond decimal value of the day
Integer array (128,2) for 128 left and right channels (NOTE 128 channels for Hi-band; 70 channels for Lo-band)
file separation variable
There is an IDL program that reads these files into an IDL-format save set. See Information URL for a link to this file.
The data are calibrated and are given in units of
'millibels' which is 1000 times the log of the received power.
Zero millbels corresponds to approximately 1.4 x 10^-21 W m^-2
Hz^-1, however, this value is never seen in practice. The
minimum values detected, which includes receiver internal and
spacecraft generated noise, are about 2300 to 2400 millibels,
or about 3.5 x 10^-19 W m^-2 Hz^-1; even higher values are seen
at the very lowest frequencies.
Note:
The polarization indicated is the received polarization, not
necessarily the emitted polarization. Correct interpretation of
the received polarization depends on the antenna plane
orientation relative to the radio source. A good description of
this concept can be found in
Leblanc Y., Aubier M. G., Ortega-Molina A.,
Lecacheux A., 1987, J.Geophys. Res. 92, 15125 and in
Wang, L. and Carr, T.D.,
Recalibration of the Voyager PRA antenna for polarization sense
measurement, Astron. Astrophys., 281, 945-954, 1994. and references therein.

(Description based on material from VG2_PRA_JUP_HRES_DS.CAT)
Voyager 2 Radio Astronomy (PRA) data from the Jupiter encounter (1979-04-25 to 1979-08-04).
The data set provides 6 second high resolution lowband radio mean power data. The data
are provided for 70 instrument channels, covering 1.2 to 1326.0 kHz.
This data set (VG2-J-PRA-3-RDR-LOWBAND-6SEC-V1.0) contains
data acquired by the Voyager-2 Planetary Radio Astronomy (PRA)
instrument during the Jupiter encounter. The bounding time
interval set for most Voyager 2 Jupiter PDS data sets is the
Voyager project defined 'far encounter' mission phase boundary
(1979-07-02 to 1979-08-03). Since, however, the PRA instrument
is able to observe planetary phenomenon at much larger ranges
than other fields and particles experiments, this boundary is
artificial with respect to PRA. Hence, PRA lowband data
provided here cover the entire Jupiter Encounter Phase
(1979-04-25 to 1979-08-04). Data from beyond the far encounter
interval is contained in the cruise data archive which is
available from the NSSDC.
VG2-J-PRA-3-RDR-LOWBAND-6SEC-V1.0 contains data at the highest
time resolution possible during normal operations. The normal
mode of PRA operations during the planetary encounters was to
sweep through the two radio receiver bands, high band (40.5 to
1.5 MHz in 128 channels spaced 0.3072 MHz apart) and low band
(1326.0 to 1.2 kHz in 70 channels spaced 19.2 kHz apart) in a
period of 6 seconds. The receivers measured, on alternate
samples, the left hand circular and right hand circular (radio
definition) power.
Measured Parameters
===================
The data here are from the low frequency receiver band and are
'packaged' into spacecraft major frame records. Each major
frame is 48 seconds long or eight sweeps through the PRA
receiver. The data are calibrated and are given in units of
'millibels' which is 1000 times the log of the received power.
Zero millbels corresponds to approximately 1.4 x 10^-21 W m^-2
Hz^-1, however, this value is never seen in practice. The
minimum values detected, which includes receiver internal and
spacecraft generated noise, are about 2300 to 2400 millibels,
or about 3.5 x 10^-19 W m^-2 Hz^-1; even higher values are seen
at the very lowest frequencies.
The data format is ASCII and consists of a time indicator
followed by an array containing the eight low band sweeps. Time
is spacecraft event time (SCET) which is basically universal
time at the spacecraft. Specifically, time is in the form of
YYMMDD and seconds into YYMMDD. Both are written as I6.
Example: July 1, 1979 at 12 hours SCET would be 790701, 43200.
The seconds correspond, to the nearest second, to the start of
the sweep (which occurs in PRA high band). The first value in
low band (1326.0 kHz) occurs some 3.9 seconds after this time
and samples at successively lower frequencies are spaced 0.03
seconds apart. Only one time is given for the entire major
frame, thus the start of each sweep is the time given plus 6
times the sweep number minus 1 (i.e., 0 through 7).
The data array is dimensioned as 71 X 8 and written as I4
format (i.e. 568I4). The '8' corresponds to the eight PRA
sweeps. The lowest 68 of the 70 low band channels (1287.6
to 1.2 kHz) are in positions 2-69. Positions 70-71 should be
ignored. Missing or bad data values are set to zero. In
position 1 of each sweep is a status word where the 12 least
significant bits have used, although not all 12 have meaning
for PRA low band. Numbering those bits 0 for least significant
to 11 for most significant, the bits that have meaning are as
follows:
bit
0: 15 dB attenuator in use when equal to 1
1: 30 dB attenuator in use when equal to 1
2: 45 dB attenuator in use when equal to 1
9,10 (together): polarization of first channel sampled (1326.0
kHz) according to the scheme:
+---------------------------+
| | |value bit|
| | | 10= |
| | | 0 | 1 |
|value bit 9=| 0 | R | L |
| | 1 | L | R |
+---------------------------+
Polarization at successively lower frequencies is opposite to
the frequency above it, i.e. either a LRLR or an RLRL pattern.
Successive 6-second sweeps start on the opposite polarization
as the previous sweep as indicated in the status bits. Note
that this polarization is the received polarization, not
necessarily the emitted polarization. Correct interpretation of
the received polarization depends on the antenna plane
orientation relative to the radio source. A good description of
this concept can be found in Leblanc Y., Aubier M. G., Ortega-Molina A.,
Lecacheux A., 1987, J.Geophys. Res. 92, 15125 and in Wang, L. and Carr, T.D.,
Recalibration of the Voyager PRA antenna for polarization sense
measurement, Astron. Astrophys., 281, 945-954, 1994. and references therein.
Missing or bad data values are set to zero. If the status word
is zero, any data in that receiver sweep should be discarded.
Data Coverage
=============
The data are stored as 4 ASCII tables (.TAB), each accompanied with a PDS
label file (.LBL) which describes properties of the data file. Data
cover the following time intervals:
Volume ID: VGPR_1201
+------------------------------------------------------------------------+
| Filename |Records| Start | Stop |
|------------------------------------------------------------------------|
| PRA_I.TAB | 32707| 1979-04-25T00:00:04.000Z |1979-05-28T23:59:14.000Z |
| PRA_II.TAB| 34207| 1979-05-29T00:00:02.000Z |1979-06-23T23:59:59.000Z |
|PRA_III.TAB| 31652| 1979-06-24T00:00:47.000Z |1979-07-12T23:59:58.000Z |
| PRA_IV.TAB| 34416| 1979-07-13T00:00:46.000Z |1979-08-04T23:05:33.000Z |
+------------------------------------------------------------------------+
Confidence Level Overview
=========================
The accuracy of calibration in the PRA low band is
approximately 2 dB, except at frequencies below 100 kHz where
it is somewhat worse. Interference from the Voyager power
subsystem is a major problem to the PRA instrument, affecting
many of the 70 low band channels. This interference manifests
itself by abrupt changes in background levels. Some channels,
notably 136 and 193 kHz, are almost always affected, whereas,
others are only affected for short intervals. Usually, this
interference is only a problem when the natural signals are
weak.
Additional information associated with this data set is available in the
following files:
+-----------------------------------------------------------------------------------------------------------------------------------+
| file | contents |
|------------------------------------------------------------------------------------------------|----------------------------------|
|http://ppi.pds.nasa.gov/ditdos/download?id=pds://PPI/VGPR_1201/CATALOG/VG2_PRA_INST.CAT | VG1 PRA instrument description |
|http://ppi.pds.nasa.gov/ditdos/download?id=pds://PPI/VGPR_1201/CATALOG/VG2_PRA_JUP_HRES_DS.CAT | data set description |
|http://ppi.pds.nasa.gov/ditdos/download?id=pds://PPI/VGPR_1201/CATALOG/PERSON.CAT |personnel information |
|http://ppi.pds.nasa.gov/ditdos/download?id=pds://PPI/VGPR_1201/CATALOG/REF.CAT |key reference description |
|http://ppi.pds.nasa.gov/ditdos/download?id=pds://PPI/VGPR_1201/DOCUMENT/INSTRUMENT |ASCII and HTML versions of the PRA|
| |investigation description paper |
+-----------------------------------------------------------------------------------------------------------------------------------+

Data Set Overview
=================
Instrument P.I. : James W. Warwick
Data Supplier : Michael L. Kaiser
Data sampling rate : 48 seconds
Data Set Start Time : 1979-04-25T00:00:00.000Z
Data Set Stop Time : 1979-08-04T23:04:00.000Z
This data set consists of edited browse data derived from an
original data set obtained from the Voyager 2 Planetary Radio
Astronomy (PRA) instrument in the vicinity of Jupiter. Data
are provided for 70 instrument channels covering the range
from 1.2 kHz to 1326 kHz in uniform 19.2 kHz steps, each 1 kHz
wide. Data are included for the period 1979-04-25 00:00:00.000
through 1979-08-04 23:04:00.000. In order to produce this data
set from the original raw PRA data, several steps have been
taken:
1. The PRA operates in a variety of modes; data from modes in
which the receiver does not scan rapidly through its frequency
range have been removed;
2. The data have been calibrated as best we know how;
3. The data have been split into Left Hand Circular (LHC) and
Right Hand Circular (RHC) components;
4. The data have been binned into 48-second intervals.
Thus, values at a given channel are separated in time by an
increment of 48 seconds; each 48-second time interval has
associated with it a value for LHC polarization and one for
RHC polarization.
During data gaps, the entire record is absent from the
data set; that is, missing records have not been zero-filled
or otherwise marked. Bad data within a record is indicated by
the value zero, which cannot otherwise occur.
Each datum is returned as a 16-bit quantity; it represents the
mean power received in the given channel at the specified time
and polarization. The returned quantity is the value in mB
about a reference flux density. To convert a returned quantity
to flux, use the formula:
flux = 7.0x10^(-22)x10^(mB/1000) W m-2 Hz-1
Parameters
==========
Data Set Parameter 'RADIO WAVE SPECTRUM'
----------------------------------------
Data Set Parameter Name : RADIO WAVE SPECTRUM
Data Set Parameter Unit : MILLIBEL
Sampling Parameter Name : TIME
Sampling Parameter Unit : SECOND
Sampling Parameter Resolution : 0.001
Sampling Parameter Interval : 48
Minimum Available Sampling Int : 12
Noise Level : 2400
A set of derived parameters consisting of power fluxes at
various contiguous frequencies over a range of frequencies.
Millibels may be converted to watts/m**2/Hz by using the
formula for flux indicated above.
Source Instrument Parameters
============================
Instrument Host ID : VG2
Data Set Parameter Name : RADIO WAVE SPECTRUM
Instrument Parameter Name : WAVE FLUX DENSITY
ELECTRIC FIELD WAVEFORM
ELECTRIC FIELD COMPONENT
MAGNETIC FIELD COMPONENT
WAVE ELECTRIC FIELD INTENSITY
WAVE MAGNETIC FIELD INTENSITY
Important Instrument Parameters : 1 (for all parameters)
Data Coverage
=============
Filename Records Start Stop
-------------------------------------------------------------------
Volume ID: VG_1502
PRA.DAT 128633 1979-04-25T00:00:00.000Z 1979-08-04T23:04:00.000Z

Data Set Overview
=================
This data set (VG2-J-PRA-3-RDR-LOWBAND-6SEC-V1.0) contains
data acquired by the Voyager-2 Planetary Radio Astronomy (PRA)
instrument during the Jupiter encounter. The bounding time
interval set for most Voyager 2 Jupiter PDS data sets is the
Voyager project defined 'far encounter' mission phase boundary
(1979-07-02 to 1979-08-03). Since, however, the PRA instrument
is able to observe planetary phenomenon at much larger ranges
than other fields and particles experiments, this boundary is
artificial with respect to PRA. Hence, PRA lowband data
provided here cover the entire Jupiter Encounter Phase
(1979-04-25 to 1979-08-04). Data from beyond the far encounter
interval is contained in the cruise data archive which is
available from the NSSDC.
VG2-J-PRA-3-RDR-LOWBAND-6SEC-V1.0 contains data at the highest
time resolution possible during normal operations. The normal
mode of PRA operations during the planetary encounters was to
sweep through the two radio receiver bands, high band (40.5 to
1.5 MHz in 128 channels spaced 0.3072 MHz apart) and low band
(1326.0 to 1.2 kHz in 70 channels spaced 19.2 kHz apart) in a
period of 6 seconds. The receivers measured, on alternate
samples, the left hand circular and right hand circular (radio
definition) power.
Measured Parameters
===================
The data here are from the low frequency receiver band and are
'packaged' into spacecraft major frame records. Each major
frame is 48 seconds long or eight sweeps through the PRA
receiver. The data are calibrated and are given in units of
'millibels' which is 1000 times the log of the received power.
Zero millbels corresponds to approximately 1.4 x 10^-21 W m^-2
Hz^-1, however, this value is never seen in practice. The
minimum values detected, which includes receiver internal and
spacecraft generated noise, are about 2300 to 2400 millibels,
or about 3.5 x 10^-19 W m^-2 Hz^-1; even higher values are seen
at the very lowest frequencies.
The data format is ASCII and consists of a time indicator
followed by an array containing the eight low band sweeps.
Time is spacecraft event time (SCET) which is basically
universal time at the spacecraft. Specifically, time is in the
form of YYMMDD and seconds into YYMMDD. Both are written as
I6. Example: July 1, 1979 at 12 hours SCET would be 790701,
43200. The seconds corresponds, to the nearest second, to the
start of the sweep (which occurs in PRA high band). The first
value in low band (1326.0 kHz) occurs some 3.9 seconds after
this time and samples at successively lower frequencies are
space 0.03 seconds apart. Only one time is given for the
entire major frame, thus the start of each sweep is the time
given plus 6 times the sweep number minus 1 (i.e., 0 through
7).
The data array is dimensioned as 71 X 8 and written as I4
format (i.e. 568I4). The '8' corresponds to the eight PRA
sweeps. The lowest 68 of the 70 low band channels (1287.6
to 1.2 kHz) are in positions 2-69. Positions 70-71 should be
ignored. Missing or bad data values are set to zero. In
position 1 of each sweep is a status word where the 12 least
significant bits have used, although not all 12 have meaning
for PRA low band. Numbering those bits 0 for least significant
to 11 for most significant, the bits that have meaning are as
follows:
bit
0: 15 dB attenuator in use when equal to 1
1: 30 dB attenuator in use when equal to 1
2: 45 dB attenuator in use when equal to 1
9,10 (together): polarization of first channel sampled
(1326.0 kHz) according to the scheme:
value bit 10 =
0 1
value bit 9 = 0 R L
1 L R
Polarization at successively lower frequencies is opposite to
the frequency above it, i.e. either a LRLR or an RLRL pattern.
Successive 6-second sweeps start on the opposite polarization
as the previous sweep as indicated in the status bits. Note
that this polarization is the received polarization, not
necessarily the emitted polarization. Correct interpretation
of the received polarization depends on the antenna plane
orientation relative to the radio source. A good description
of this concept can be found in [LEBLANCETAL1987].
Missing or bad data values are set to zero. If the status word
is zero, any data in that receiver sweep should be discarded.
Data Coverage
=============
Filename Records Start Stop
-----------------------------------------------------------------------
Volume ID: VGPR_1201
PRA_I.TAB 32707 1979-04-25T00:00:04.000Z 1979-05-28T23:59:14.000Z
PRA_II.TAB 34207 1979-05-29T00:00:02.000Z 1979-06-23T23:59:59.000Z
PRA_III.TAB 31652 1979-06-24T00:00:47.000Z 1979-07-12T23:59:58.000Z
PRA_IV.TAB 34416 1979-07-13T00:00:46.000Z 1979-08-04T23:05:33.000Z

Data Set Overview
=================
This data set consists of electric field spectrum analyzer data
from the Voyager 2 Plasma Wave Subsystem obtained during the
entire mission. Data after 2013-12-31 will be added to the archive
on subsequent volumes. The data set encompasses all spectrum
analyzer observations obtained in the cruise mission phases
before, between, and after the Jupiter and Saturn encounter phases
as well as those obtained during the two encounter phases.
The Voyager 2 spacecraft travels from Earth to beyond 80 AU over
the course of this data set. To provide some guidance on when
some key events occurred during the mission, the following table
is provided.
Date Event
1977-08-20 Launch
1979-07-02 First inbound bow shock crossing at Jupiter
1979-08-03 Last outbound bow shock crossing at Jupiter
1981-08-24 First inbound bow shock crossing at Saturn
1981-08-31 Last outbound bow shock crossing at Saturn
1982-04-26 10 AU
1983-08-30 Onset of first major LF heliospheric radio event
1986-01-24 First inbound bow shock crossing at Uranus
1986-01-29 Last outbound bow shock crossing at Uranus
1986-05-26 20 AU
1989-08-07 30 AU
1989-08-24 First inbound bow shock crossing at Neptune
1989-08-28 Last outbound bow shock crossing at Neptune
1992-07-06 Onset of second major LF heliospheric radio event
1993-05-08 40 AU
1996-10-10 50 AU
2000-01-27 60 AU
2002-11-01 Onset of third major LF heliospheric radio event
2003-04-21 70 AU
2006-07-01 80 AU
2009-09-03 90 AU
2012-11-04 100 AU
Data Sampling
=============
This data set consists of full resolution edited, wave electric
field intensities from the Voyager 2 Plasma Wave Receiver spectrum
analyzer obtained during the entire mission. For each time
interval, a field strength is determined for each of the 16
spectrum analyzer channels whose center frequencies range from 10
Hertz to 56.2 kiloHertz and which are logarithmically spaced in
frequency, four channels per decade. The time associated with
each set of intensities (16 channels) is the time of the beginning
of the scan. The time between spectra in this data set vary by
telemetry mode and range from 4 seconds to 96 seconds. During
data gaps where complete spectra are missing, no entries exist in
the file, that is, the gaps are not zero-filled or tagged in any
other way. When one or more channels are missing within a scan,
the missing measurements are zero-filled. Data are edited but not
calibrated. The data numbers in this data set can be plotted in
raw form for event searches and simple trend analysis since they
are roughly proportional to the log of the electric field
strength. Calibration procedures and tables are provided for use
with this data set; the use of these is described below.
For the cruise data sets, the timing of samples is dependent upon
the spacecraft telemetry mode. In principle, one can determine
the temporal resolution between spectra simply by noting the
difference in time between two records in the files. In some
studies, more precise timing information is necessary. Here, we
describe the timing of the samples for the PWS low rate data as a
function of telemetry mode.
The PWS instrument uses two logarithmic compressors as detectors
for the 16-channel spectrum analyzer, one for the bottom (lower
frequency) 8 channels, and one for the upper (higher frequency) 8
channels. For each bank of 8 channels, the compressor
sequentially steps from the lowest frequency of the 8 to the
highest in a regular time step to obtain a complete spectrum. At
each time step, the higher frequency channel is sampled 1/8 s
prior to the lower frequency channel so that the channels are
sampled in the following order with channel 1 being the lowest
frequency channel (10 Hz) and 16 being the highest (56.2 kHz): 9,
1, 10, 2, 11, 3, ... 15, 7, 16, 8. The primary difference
between the various data modes is the stepping rate from one
channel to the next (ranging from 0.5 to 12 s, corresponding to
temporal resolutions between complete spectra of 4 s to 96 s).
In the following table, we present the hexadecimal id for the
various telemetry modes, the mode mnemonic ID, the time between
frequency steps, and the time between complete spectra. We also
provide the offset from the beginning of the instrument cycle (one
complete spectrum) identified as the time of each record's time
tag to the time of the sampling for the first high-frequency
channel (channel 9) and for the first low-frequency channel
(channel 1).
Time
Frequency Between High Freq. Low Freq.
MODE (Hex) MODE ID Step (s) Spectra (s) offset (s) offset (s)
01 CR-2 0.5 4.0 0.425 0.4325
02 CR-3 1.2 9.6 1.125 1.1325
03 CR-4 4.8 38.4 0.425 0.4325
04 CR-5 9.6 76.8 0.425 0.4325
05 CR-6 12. 96.0 0.9275 0.935
06 CR-7 NOT IMPLEMENTED
07 CR-1 0.5 4.0 0.225 0.2325
08 GS-10A SAME AS GS-3
0A GS-3 0.5 4.0 0.425 0.4325
0C GS-7 SAME AS GS-3
0E GS-6 SAME AS GS-3
16 OC-2 SAME AS GS-3
17 OC-1 SAME AS GS-3
18 **CR-5A 0.5 4.0 0.425 0.4325
19 GS-10 SAME AS GS-3
1A GS-8 SAME AS GS-3
1D **UV-5A SAME AS CR-5A
**In CR-5A and UV-5A, the PWS is cycled at its 0.5 sec/frequency
step or 4 sec/spectrum rate, but 4 measurements are summed on
board in 10-bit accumulators and these 10-bit sums are downlinked.
On the ground, the sums are divided by 4, hence providing, in a
sense, 16-second averages. One of every 12 sets of sums is
dropped on board in order to avoid LECP stepper motor
interference.
Data Processing
===============
The spectrum analyzer data are a continuous (where data are
available) low resolution data set which provides wave intensity as
a function of frequency (16 log-spaced channels) and time (one
spectrum per time intervals ranging from 4 seconds to 96 seconds,
depending on telemetry mode). The data are typically plotted as
amplitude vs. time for one or more of the channels in a strip-chart
like display, or can be displayed as a frequency-time spectrogram
using a gray- or color-bar to indicate amplitude. With only sixteen
channels, it is usually best to stretch the frequency axis by
interpolating from one frequency channel to the next either linearly
or with a spline fit. One must be aware if the frequency axis is
stretched that more resolution may be implied than is really
present. The Voyager PWS calibration table is given in an ASCII
text file named VG2PWSCL.TAB (for Voyager-2). This provides
information to convert the uncalibrated 'data number' output of the
PWS 16-channel spectrum analyzer to calibrated antenna voltages for
each frequency channel. Following is a brief description of this
file and a tutorial in its application.
Descriptive headers have been removed from this file. The columns
included are IDN, ICHAN01, ICHAN02, ICHAN03, ICHAN04, ICHAN05,
ICHAN06, ... ICHAN16.
The first column lists an uncalibrated data number followed by the
corresponding value in calibrated volts for each of the 16
frequency channels of the PWS spectrum analyzer. Each line
contains calibrations fo

Data Set Overview
=================
This data set consists of electric field waveform samples from
the Voyager 2 Plasma Wave Subsystem waveform receiver obtained
during the entire mission. Data after 2006-03-07 will be added to the
archive on subsequent volumes. The data set encompasses all
waveform observations obtained in the cruise mission phases
before, between, and after the Jupiter, Saturn, Uranus, and
Neptune encounter phases as well as those obtained during the
four encounter phases.
The Voyager 2 spacecraft travels from Earth to beyond 80 AU over
the course of this data set. To provide some guidance on when
some key events occurred during the mission, the following table
is provided.
Date Event
1977-08-20 Launch
1979-07-02 First inbound bow shock crossing at Jupiter
1979-08-03 Last outbound bow shock crossing at Jupiter
1981-08-24 First inbound bow shock crossing at Saturn
1981-08-31 Last outbound bow shock crossing at Saturn
1982-04-26 10 AU
1983-08-30 Onset of first major LF heliospheric radio event
1986-01-24 First inbound bow shock crossing at Uranus
1986-01-29 Last outbound bow shock crossing at Uranus
1986-05-26 20 AU
1989-08-07 30 AU
1989-08-24 First inbound bow shock crossing at Neptune
1989-08-28 Last outbound bow shock crossing at Neptune
1992-07-06 Onset of second major LF heliospheric radio event
1993-05-08 40 AU
1996-10-10 50 AU
2000-01-27 60 AU
2002-11-01 Onset of third major LF heliospheric radio event
2003-04-21 70 AU
2006-07-01 80 AU
2009-09-03 90 AU
2012-11-04 100 AU
Data Sampling
=============
The waveform is sampled at 4-bit resolution through a bandpass
filter with a passband of 40 Hz to 12 kHz. 1600 samples are
collected in 55.56 msec (at a rate of 28,800 samples per second)
followed by a 4.44-msec gap. Each 60-msec interval constitutes
a line of waveform samples. The data set includes frames of
waveform samples consisting of up to 800 lines, or 48 seconds,
each. The telemetry format for the waveform data is identical
to that for images, hence the use of line and frame as
constructs in describing the form of the data.
Data Processing
===============
Because there is no direct method for calibrating these data and
because the raw format of packed, 4-bit samples is
space-efficient, these data are not processed for archiving.
The data may be plotted in raw form to show the actual waveform;
this is useful for studying events such as dust impacts on the
spacecraft. But the normal method of analyzing the waveform
data is by Fourier transforming the samples from each line to
arrive at an amplitude versus frequency spectrum. By stacking
the spectra side-by-side in time order, a frequency-time
spectrogram can be produced.
Data
====
The waveforms are collections of samples of the electric field
measured by the dipole electric antenna at a rate of 28,800
samples per second. The 4-bit samples provide sixteen digital
values of the electric field with a linear amplitude scale, but
the amplitude scale is arbitrary because of the automatic gain
control used in the waveform receiver. The instantaneous
dynamic range afforded by the 4 bit samples is about 23 dB, but
the automatic gain control allows the dominant signal in the
passband to be set at the optimum level to fit within the
instantaneous dynamic range. With the gain control, the overall
dynamic range of the waveform receiver is about 100 dB. The
automatic gain control gain setting is not returned to the
ground, hence, there is no absolute calibration for the data.
However, by comparing the waveform spectrum derived by Fourier
transforming the waveform to the spectrum provided by the
spectrum analyzer data, an absolute calibration may be obtained
in most cases.
Ancillary Data
==============
None
Coordinates
===========
The electric dipole antenna detects electric fields in a dipole
pattern with peak sensitivity parallel to the spacecraft x-axis.
However, no attempt has been made to correlate the measured
field to any particular direction such as the local magnetic
field or direction to a planet. This is because the spacecraft
remains in a 3-axis stabilized orientation almost continuously,